BUG#17460821

Automerged from mysql-5.5 bug branch into latest mysql-5.5.

plugin/semisync/semisync_master.cc

@@ -482,6 +482,9 @@ void ReplSemiSyncMaster::remove_slave()
   lock();
   rpl_semi_sync_master_clients--;
 
+  /* Only switch off if semi-sync is enabled and is on */
+  if (getMasterEnabled() && is_on())
+  {
     /* If user has chosen not to wait if no semi-sync slave available
        and the last semi-sync slave exits, turn off semi-sync on master
        immediately.
@@ -489,6 +492,7 @@ void ReplSemiSyncMaster::remove_slave()
     if (!rpl_semi_sync_master_wait_no_slave &&
         rpl_semi_sync_master_clients == 0)
       switch_off();
+  }
   unlock();
 }