Bug #50449 Agent reports old timestamps for mysqld info under corner case

Description:
It is possible to get the agent in a state where it will report mysqld data with an old timestamp.

How to repeat:
With the agent log in debug mode do:

1- start an agent against a running instance properly
2- change the agent password (the one that the agent uses to connect to 
mysqld
2.5- flush privileges ;
3- stop the mysqld instance
4- start the mysqld instance
5- check what times are being reported for dc in the debug logs
6- the agent should *not* be able to reconnect to the db..

To verify 6 you can do: 

$ tail -f agent.log | grep critical

To verify 5 do: 

$ tail -f agent.log | grep utc

and you would see something like 

============
<utc>2010-01-19T16:00:07.312Z</utc>
     <utc>2010-01-19T15:52:01.296Z</utc>
   <utc>2010-01-19T16:00:07.312Z</utc>
     <utc>2010-01-19T16:00:01.331Z</utc>
   <utc>2010-01-19T16:00:07.312Z</utc>
     <utc>2010-01-19T15:52:01.296Z</utc>
   <utc>2010-01-19T16:00:07.313Z</utc>
     <utc>2010-01-19T16:00:01.331Z</utc>
===========
Note the entries with 15:52:01, those are the wrong value, they should all be 16:00 (or close to that)

data showing the old timestamp 

<task>
   <taskId>33417</taskId>
   <command>collect_data</command>
   <utc>2010-01-19T16:01:07.321Z</utc>
   <data>
    <datum>
     <target>
      <namespace>mysql</namespace>
      <classname>variables</classname>
      <instance>c02e030a-c5be-4b39-b34e-8fad04b72985</instance>
      <attribute>query_cache_size</attribute>
     </target>
     <utc>2010-01-19T15:52:01.303Z</utc>
     <value>0</value>
    </datum>
   </data>
  </task>
  <task>

--------------
  <task>
   <taskId>33371</taskId>
   <command>collect_data</command>
   <utc>2010-01-19T16:01:07.321Z</utc>
   <data>
    <datum>
     <target>
      <namespace>mysql</namespace>
      <classname>variables</classname>
      <instance>c02e030a-c5be-4b39-b34e-8fad04b72985</instance>
      <attribute>max_connections</attribute>
     </target>
     <utc>2010-01-19T15:52:01.303Z</utc>
     <value>151</value>
    </datum>
   </data>
  </task>
  <task>

----------------------
  <task>
   <taskId>33342</taskId>
   <command>collect_data</command>
   <utc>2010-01-19T16:01:07.321Z</utc>
   <data>
    <datum>
     <target>
      <namespace>mysql</namespace>
      <classname>variables</classname>
      <instance>c02e030a-c5be-4b39-b34e-8fad04b72985</instance>
      <attribute>key_cache_block_size</attribute>
     </target>
     <utc>2010-01-19T15:52:01.303Z</utc>
     <value>1024</value>
    </datum>
   </data>
  </task>
  <task>

Diego Medina writes: 
Agent log in debug mode

Keith Russell writes: 
Patch installed in versions => 2.1.1.1145.

Diego Medina writes: 
Never mind my last comment, it was fixed.

A note has been added to the 2.1.1 changelog: 

        The &merlin_agent; could report data using an old timestamp,                                                                     
        or report information for a server that the &merlin_agent; can                                                                   
        no longer connect to due to a permissions change.