fix vargrind errors of Spider (#1273)

* Fix valgrind error caused by vp/spider.handler test.

* Fix valgrind error caused by vp/spider.ha test.

storage/spider/spd_sys_table.cc

@@ -2427,6 +2427,7 @@ int spider_get_sys_tables_static_link_id(
 ) {
   int error_num = 0;
   DBUG_ENTER("spider_get_sys_tables_static_link_id");
+  *static_link_id = NULL;
   if (
     !table->field[24]->is_null() &&
     (*static_link_id = get_field(mem_root, table->field[24]))

storage/spider/spd_table.cc

@@ -8473,16 +8473,9 @@ void spider_free_tmp_dbton_handler(
 TABLE_LIST *spider_get_parent_table_list(
   ha_spider *spider
 ) {
-  TABLE *table = spider->get_table();
-  TABLE_LIST *table_list = table->pos_in_table_list;
+  TABLE *table = spider->get_top_table();
   DBUG_ENTER("spider_get_parent_table_list");
-  if (table_list)
-  {
-    while (table_list->parent_l)
-      table_list = table_list->parent_l;
-    DBUG_RETURN(table_list);
-  }
-  DBUG_RETURN(NULL);
+  DBUG_RETURN(table->pos_in_table_list);
 }
 
 List<Index_hint> *spider_get_index_hints(