title: use tf.nn.dynamic_rnn but final state don't have c and h
body: <p>I'm working with tensorflow, I want run a program with RNN, but I got the followed error:</p>
  
  <pre><code>a=self._encoder_final_state[0].c
  AttributeError: 'Tensor' object has no attribute 'c'
  </code></pre>
  
  <p>the program is like this:</p>
  
  <pre><code>self._encoder_cells = build_rnn_layers(
      cell_type=self._hparams.cell_type,
      num_units_per_layer=self._num_units_per_layer,
      use_dropout=self._hparams.use_dropout,
      dropout_probability=self._hparams.dropout_probability,
      mode=self._mode,
      residual_connections=self._hparams.residual_encoder,
      highway_connections=self._hparams.highway_encoder,
      dtype=self._hparams.dtype,
  )
  
  self._encoder_outputs, self._encoder_final_state = tf.nn.dynamic_rnn(
      cell=self._encoder_cells,
      inputs=encoder_inputs,
      sequence_length=self._inputs_len,
      parallel_iterations=self._hparams.batch_size[0 if self._mode == 'train' else 1],
      swap_memory=False,
      dtype=self._hparams.dtype,
      scope=scope,
  )
  a=self._encoder_final_state[0].c
  </code></pre>