MDEV-82 : Fix place in thr_lock.c where wait-end callback was called without...

MDEV-82 : Fix place in thr_lock.c where wait-end callback was called without corresponding wait-begin

mysys/thr_lock.c

@@ -482,6 +482,7 @@ wait_for_lock(struct st_lock_list *wait, THR_LOCK_DATA *data,
   struct timespec wait_timeout;
   enum enum_thr_lock_result result= THR_LOCK_ABORTED;
   const char *old_proc_info;
+  my_bool use_wait_callbacks;
   DBUG_ENTER("wait_for_lock");
 
   /*
@@ -534,7 +535,12 @@ wait_for_lock(struct st_lock_list *wait, THR_LOCK_DATA *data,
     and once after the thread has exited the wait loop.
    */
   if ((!thread_var->abort || in_wait_list) && before_lock_wait)
+  {
+    use_wait_callbacks= TRUE;
     (*before_lock_wait)();
+  }
+  else
+    use_wait_callbacks= FALSE;
 
   set_timespec(wait_timeout, lock_wait_timeout);
   while (!thread_var->abort || in_wait_list)
@@ -572,7 +578,7 @@ wait_for_lock(struct st_lock_list *wait, THR_LOCK_DATA *data,
     We call the after_lock_wait callback once the wait loop has
     finished.
    */
-  if (after_lock_wait)
+  if (after_lock_wait && use_wait_callbacks)
     (*after_lock_wait)();
 
   DBUG_PRINT("thr_lock", ("aborted: %d  in_wait_list: %d",