Py3 fixes

PiperOrigin-RevId: 172172540

Author: Ryan Sepassi

tensor2tensor/data_generators/cnn_dailymail.py

@@ -74,7 +74,7 @@ def story_generator(tmp_dir):
   for path in paths:
     for story_file in tf.gfile.Glob(path + "*"):
       story = u""
-      for line in tf.gfile.Open(story_file):
+      for line in tf.gfile.Open(story_file, "rb"):
         line = unicode(line, "utf-8") if six.PY2 else line.decode("utf-8")
         story += line
       yield story

tensor2tensor/utils/beam_search_test.py

@@ -318,7 +318,7 @@ def symbols_to_logits(ids, states):
       # Catch and fail so that the testing framework doesn't think it's an error
       try:
         sess.run(final_ids)
-      except tf.errors.InvalidArgumentError, e:
+      except tf.errors.InvalidArgumentError as e:
         raise AssertionError(e.message)
 
   def testStateBeamTwo(self):
@@ -366,7 +366,7 @@ def symbols_to_logits(ids, states):
       # Catch and fail so that the testing framework doesn't think it's an error
       try:
         sess.run(final_ids)
-      except tf.errors.InvalidArgumentError, e:
+      except tf.errors.InvalidArgumentError as e:
         raise AssertionError(e.message)
 
 if __name__ == "__main__":