Revert part of last change, it was not related to a security fix.

mysys/thr_lock.c

@@ -333,10 +333,10 @@ void thr_lock_init(THR_LOCK *lock)
 void thr_lock_delete(THR_LOCK *lock)
 {
   DBUG_ENTER("thr_lock_delete");
+  VOID(pthread_mutex_destroy(&lock->mutex));
   pthread_mutex_lock(&THR_LOCK_lock);
   thr_lock_thread_list=list_delete(thr_lock_thread_list,&lock->list);
   pthread_mutex_unlock(&THR_LOCK_lock);
-  pthread_mutex_destroy(&lock->mutex);
   DBUG_VOID_RETURN;
 }