In certain rare cases when a process was interrupted
during a FLUSH PRIVILEGES operation the diagnostic
area would be set to an error state but the function
responsible for the operation would still signal
success. This would lead to a debug assertion error
later on when the server would attempt to reset the
DA before sending the error message.

This patch fixes the issue by assuring that
reload_acl_and_cache() always fails if an error
condition is raised.

The second issue was that a KILL could cause
a console error message which referred to a DA
state without first making sure that such a
state existed.

This patch fixes this issue in two different
palces by first checking DA state before
fetching the error message.

 

sql/sql_acl.cc:
  * Make sure that there is an error to print before attempting to do so.
  * Minor style change: change 1 to TRUE for clarity.
sql/sql_parse.cc:
  * Always fail reload_acl_and_cache() if the query was killed.
sql/sql_servers.cc:
  * Make sure that there is an error to print before attempting to do so.