fix failed index errorly release snapshot

src/rootserver/ob_index_builder.cpp

@@ -540,6 +540,7 @@ int ObRSBuildIndexTask::process()
     if (OB_FAIL(report_index_status(index_status))) {
       LOG_WARN("fail to report index status", K(ret));
       need_retry_ = true;
+      need_release_snapshot = false;
     }
   }
   if (need_release_snapshot) {

src/sql/engine/cmd/ob_index_executor.cpp

@@ -235,12 +235,8 @@ int ObCreateIndexExecutor::sync_check_index_status(sql::ObSQLSessionInfo& my_ses
       LOG_WARN("fail to get index table schema", KR(ret), K(refreshed_schema_version), K(index_table_id));
     } else if (OB_ISNULL(index_schema)) {
       // maybe ddl(drop index,drop table,truncate table) in another session has dropped this index.
-      if (!is_update_global_indexes) {
-        ret = OB_ERR_ADD_INDEX;
-        LOG_USER_ERROR(OB_ERR_ADD_INDEX);
-      } else {
-        ret = OB_ERR_UNEXPECTED;
-      }
+      ret = OB_ERR_ADD_INDEX;
+      LOG_USER_ERROR(OB_ERR_ADD_INDEX);
       LOG_WARN("index table schema is null",
           KR(ret),
           K(index_table_id),