Bug #9993 2 unexpected warnings when dropping a routine and --skip-grant-tables

Description:
In mysql-test:

create t/sp_bug.test with this:
create procedure foo() select 1;
drop procedure foo;

Create t/sp_bug-master.opt with this:
--skip-grant-tables

and create an empty r/sp_bug.result, then run this test, and the output is:
+ create procedure foo() select 1;
+ drop procedure foo;
+ Warnings:
+ Error 1290    The MySQL server is running with the --skip-grant-tables option so it cannot execute this statement
+ Warning       1405    Failed to revoke all privileges to dropped routine

Those two warnings are not expected. It can execute the DROP, so the "statement" the first warning refers to is probably an internally generated statement for which the user should not be notified. The 2nd warning should also not be there as we're not using privilege tables.
Note that this isn't about a weird "mysql" database setup: the "mysql" database was properly created by the testsuite, there is a mysql.proc; we are just legally using --skip-grant-tables to not use privileges.

How to repeat:
see description

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/internals/25295

Pushed to 5.0.7

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/internals/25344

Thank you for your bug report. This issue has been addressed in the
documentation. The updated documentation will appear on our website
shortly, and will be included in the next release of the relevant
product(s).

Additional info:

Documented fixes in changelogs for 5.0.7 and 5.0.8; marked bug as Closed.