message: Add trainable property to DistributedVariable.
diff: @@ -534,6 +534,10 @@ class DistributedVariable(DistributedDelegate):
  def shape(self):
  return self.primary.shape
  + @property
  + def trainable(self):
  + return self.primary.trainable
  +
  @property
  def distribute_strategy(self):
  return self._distribute_strategy
  