private static void correctAutoStartMechanism(Configuration conf) {
    final String autoStartKey = "datanucleus.autoStartMechanismMode";
    final String autoStartIgnore = "ignored";
    String currentAutoStartVal = conf.get(autoStartKey);
    if (currentAutoStartVal == null) {
      LOG.info("Configuration {} is not set. Defaulting to '{}'", autoStartKey,
          autoStartIgnore);
      currentAutoStartVal = autoStartIgnore;
    }
    if (!autoStartIgnore.equalsIgnoreCase(currentAutoStartVal)) {
      LOG.warn("{} is set to unsupported value {} . Setting it to value: {}", autoStartKey,
          conf.get(autoStartKey), autoStartIgnore);
    }
    conf.set(autoStartKey, autoStartIgnore);
  }
Update conf to set datanucleus.autoStartMechanismMode=ignored.
This is necessary to able to use older version of hive against
an upgraded but compatible metastore schema in db from new version
of hive

@param conf
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/PersistenceManagerProvider.java