sql_db.cc:

  Bug#19392: Rename Database: Crash if case change
  Additional minor fix, to avoid compiler warnings.

sql/sql_db.cc

@@ -134,8 +134,8 @@ void lock_db_delete(const char *name, uint length)
 {
   my_dblock_t *opt;
   safe_mutex_assert_owner(&LOCK_lock_db);
-  if (opt= (my_dblock_t *)hash_search(&lock_db_cache,
-                                      (const byte*) name, length))
+  if ((opt= (my_dblock_t *)hash_search(&lock_db_cache,
+                                       (const byte*) name, length)))
     hash_delete(&lock_db_cache, (byte*) opt);
 }