Fix of using uninitialized variadle.

sql/sql_select.cc

@@ -15674,6 +15674,8 @@ create_internal_tmp_table_from_heap2(THD *thd, TABLE *table,
   const char *save_proc_info;
   int write_err= 0;
   DBUG_ENTER("create_internal_tmp_table_from_heap2");
+  if (is_duplicate)
+    *is_duplicate= FALSE;
 
   if (table->s->db_type() != heap_hton || 
       error != HA_ERR_RECORD_FILE_FULL)

sql/sql_union.cc

@@ -83,7 +83,7 @@ int select_union::send_data(List<Item> &values)
       */
       return -1;
     }
-    bool is_duplicate;
+    bool is_duplicate= FALSE;
     /* create_internal_tmp_table_from_heap will generate error if needed */
     if (table->file->is_fatal_error(write_err, HA_CHECK_DUP) &&
         create_internal_tmp_table_from_heap(thd, table,