message: Delete infeasible TODO in CudnnRNN
  Nvidia CuDNN7 still uses old GRU equations.
diff: @@ -105,9 +105,6 @@ class CudnnCompatibleGRUCell(rnn_cell_impl.GRUCell):
  ```python
  r .* (h * R) != (r .* h) * R
  ```
  -
  - TODO(jamesqin): update the impl after Cudnn 7.1 when Nvidia would adopt the
  - canonical version compatible with other tf GRU cells.
  """
  def __init__(self, num_units, reuse=None, kernel_initializer=None):
  