message: Fix conflict.
  Use the exposed Scaffold.default_init_op instead of _default_init_op.
diff: @@ -636,11 +636,9 @@ class Estimator(object):
  sharded=True)
  saver_for_restore.restore(session, checkpoint_path)
  - # pylint: disable=protected-access
  local_init_op = (
  estimator_spec.scaffold.local_init_op or
  - monitored_session.Scaffold._default_local_init_op())
  - # pylint: enable=protected-access
  + monitored_session.Scaffold.default_local_init_op())
  # Perform the export
  builder = saved_model_builder.SavedModelBuilder(temp_export_dir)
  