message: Fix python3 compatibility for test
  Binary strings need to be decoded before being compared to
  utf-8 strings.
diff: @@ -963,7 +963,7 @@ class SummaryOpsTest(test_util.TensorFlowTestCase):
  Activation('relu', name='my_relu')])
  event = self.keras_model(name='my_name', data=model, step=1)
  first_val = event.summary.value[0]
  - self.assertEqual(model.to_json(), first_val.tensor.string_val[0])
  + self.assertEqual(model.to_json(), first_val.tensor.string_val[0].decode())
  @test_util.run_v2_only
  def testKerasModel_usesDefaultStep(self):
  