Bug #49127 Removing Obsolete Server Fail

Description:
Removing obsolete server, which is not present at all, failed due to NPE. The snippet from the log follows:

java.lang.NullPointerException
at com.mysql.etools.monitor.migrate.HibMigrator$47.run(HibMigrator.java:1876)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at com.mysql.etools.monitor.pom.hib.HibPersistence$45.call(HibPersistence.java:1322)
at com.mysql.etools.monitor.pom.hib.HibernateExecutor$1.execute(HibernateExecutor.java:142)
at com.mysql.etools.monitor.pom.hib.HibernateExecutor.asTransaction(HibernateExecutor.java:190)
at com.mysql.etools.monitor.pom.hib.HibernateExecutor.asTransaction(HibernateExecutor.java:150)
at com.mysql.etools.monitor.pom.hib.HibPersistence.asTransaction(HibPersistence.java:1300)
at com.mysql.etools.monitor.pom.hib.HibPersistence.synchronizedTransaction(HibPersistence.java:1319)
at com.mysql.etools.monitor.pom.hib.HibPersistence.synchronizedTransaction(HibPersistence.java:1314)
at com.mysql.etools.monitor.migrate.HibMigrator.remove(HibMigrator.java:1871)
at com.mysql.etools.monitor.bo.Manager.remove(Manager.java:562)
at com.mysql.merlin.ui.actions.settings.servers.DeleteServer.executeInner(DeleteServer.java:51)
at com.mysql.merlin.ui.actions.BaseJSONAction.exec(BaseJSONAction.java:200)
at com.mysql.merlin.ui.actions.BaseAction$1.call(BaseAction.java:1729)
at com.mysql.merlin.ui.actions.BaseAction$1.call(BaseAction.java:1728)
at com.mysql.merlin.ui.actions.BaseAction.execute(BaseAction.java:1712)
at com.mysql.merlin.ui.actions.BaseAction.execute(BaseAction.java:1727)
at sun.reflect.GeneratedMethodAccessor2276.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:404)
at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:267)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:229)
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:167)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86)
at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:1)
at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:170)
at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:1)
at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
at com.mysql.merlin.ui.interceptors.InitializeInterceptor.intercept(InitializeInterceptor.java:82)
at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:1)
at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:176)
at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:1)
at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
at org.apache.struts2.interceptor.TokenInterceptor.handleValidToken(TokenInterceptor.java:172)
at org.apache.struts2.interceptor.TokenInterceptor.doIntercept(TokenInterceptor.java:138)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86)
at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:1)
at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
at com.mysql.merlin.ui.interceptors.AuthenticationInterceptor.intercept(AuthenticationInterceptor.java:118)
at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:224)
at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:1)
at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:221)
at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:50)
at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:507)
at org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:421)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at net.sf.ehcache.constructs.web.filter.GzipFilter.doFilter(GzipFilter.java:75)
at net.sf.ehcache.constructs.web.filter.Filter.doFilter(Filter.java:92)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.mysql.util.RequestCounterFilter.doFilter(RequestCounterFilter.java:117)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.mysql.merlin.ui.filters.AccessLogFilter.doFilter(AccessLogFilter.java:56)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:263)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:584)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Unknown Source)

How to repeat:
Remove a monitored server from "Global Settings -> Manage Servers" page.

Suggested fix:
n/a