message: Fix NoneType error in tf.nn.depthwise_conv2d with unknown shape
  This fix tries to address the issue raised in 22110 where
  tf.nn.depthwise_conv2d thowns out NoneType error when the input
  shape is unknown.
  This fix fixes 22110.
diff: @@ -510,7 +510,7 @@ class _WithSpaceToBatch(object):
  # Recover channel information for output shape if channels are not last.
  if self.data_format is not None and self.data_format.startswith("NC"):
  - if not result_converted.shape[1].value:
  + if not result_converted.shape[1].value and filter is not None:
  output_shape = result_converted.shape.as_list()
  output_shape[1] = filter.shape[-1]
  result_converted.set_shape(output_shape)
  