message: [TFE] Return a byte-encoded value for tfe.defun's name
  This is necessary when the function object is passed to an op constructor;
  the op's func attribute is a protobuf field and must be bytes in python3.
diff: @@ -422,7 +422,8 @@ class GraphModeFunction(object):
  @property
  def name(self):
  - return self._function_def.name
  + """Returns the name of the function in Eager-compatible format."""
  + return self._function_def.name.encode("utf-8")
  def add_to_graph(self, g):
  if self._function_def.name not in g._functions: # pylint: disable=protected-access
  