private static void closeDagClientWithoutEx(DAGClient dagClient) {
    try {
      dagClient.close();
    } catch (Exception e) {
      LOG.warn("Failed to close DagClient", e);
    }
  }
Close DagClient, log warning if it throws any exception.
We don't want to fail query if that function fails.
ql/src/java/org/apache/hadoop/hive/ql/exec/tez/TezTask.java