Correct DBUG_ENTER for Pushdown_derived::execute

Author: grooverdan

sql/derived_handler.cc

@@ -52,7 +52,7 @@ int Pushdown_derived::execute()
  TABLE *table= handler->table;
  TMP_TABLE_PARAM *tmp_table_param= handler->tmp_table_param;
 
- DBUG_ENTER("Pushdown_query::execute");
+ DBUG_ENTER("Pushdown_derived::execute");
 
  if ((err= handler->init_scan()))
  goto error;