@Override
  public boolean beforeMigration() {
    return migrationContext.getOriginDataVersion() == 0;
  }
Called by the framework before migration.
Supports only migration from version 1.0.0, so we cancel migration
if the origin version is not 0.

@return true if migration started against the instance with data version "0"
ambari-views/examples/phone-list-upgrade-view/src/main/java/org/apache/ambari/view/phonelist/DataMigrator.java