Backporting a patch for Bug#43138. That patch had been already backported

to 5.1 partially. This patch brings what was left to mysql-next-mr.

Original revisions in 6.0:
------------------------------------------------------------
revno: 2617.31.26
committer: Alexander Nozdrin <alik@sun.com>
branch nick: 6.0-rt-bug43138.3
timestamp: Thu 2009-04-30 19:31:30 +0400
message:
  Fix for Bug#43138: DROP DATABASE failure does not clean up message list.
  
  The problem was that the high-level function mysql_rm_db() invoked
  low-level mysql_rm_table_part2(), which reported low-level error
  (Unknown table) if SE refused to delete a table. Also when
  mysql_rm_table_part2() reported an error, it didn't add corresponding
  warning into the list (because it is used from other places where such
  behaviour is required).
  
  The fix is to
    1. Remove no_warnings_for_error usage from sql_table.cc
    2. Improve internal error handler support in THD, so that
       a stack of error handlers is allowed.
    3. Create an internal error handler (Drop_table_error_handler)
       to silence useless warnings.
    4. Use the handler in DROP DATABASE and DROP TABLE statements.
------------------------------------------------------------
revno: 2617.69.38
committer: Alexander Nozdrin <alik@sun.com>
branch nick: mysql-next-bugfixing-bug37431
timestamp: Mon 2009-08-24 21:52:09 +0400
message:
  A test case for Bug#37431 (DROP TABLE does not report errors correctly).
------------------------------------------------------------
revno: 2617.31.29
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-runtime
timestamp: Fri 2009-05-01 17:37:34 +0400
message:
  Follow-up for fix for bug "Bug#43138: DROP DATABASE failure
  does not clean up message list".
  
  Fixed drop.test failure under non-debug server by moving part
  of test dependent on debug-only feature to separate .test file,
  which won't be run for non-debug versions of server.
------------------------------------------------------------
revno: 2617.45.17
committer: Sergei Golubchik <serg@mysql.com>
branch nick: 6.0-maria
timestamp: Wed 2009-05-13 20:08:58 +0200
message:
  followup for bug#43138
  if delete fails with a permission denied error, we want to show it
------------------------------------------------------------

The patch was backported to 5.1 in scope of Bug#42364 by
the following revision:
------------------------------------------------------------
revno: 2497.975.3
committer: Sergey Glukhov <Sergey.Glukhov@sun.com>
branch nick: mysql-5.1-bugteam
timestamp: Fri 2009-07-03 13:22:06 +0500
message:
  Bug#42364 SHOW ERRORS returns empty resultset after dropping non existent table
  enabled message storing into error message list
  for 'drop table' command
------------------------------------------------------------

sql/sql_class.cc

@@ -390,7 +390,7 @@ char *thd_security_context(THD *thd, char *buffer, unsigned int length,
 
 
 /**
-  Implementation of Drop_table_error_handler::handle_error().
+  Implementation of Drop_table_error_handler::handle_condition().
   The reason in having this implementation is to silence technical low-level
   warnings during DROP TABLE operation. Currently we don't want to expose
   the following warnings during DROP TABLE: