message: fix the comments which mistake x for y
diff: @@ -181,7 +181,7 @@ def _compute_numeric_jacobian(x, x_shape, x_data, y, y_shape, delta,
  def _compute_dx_and_dy(x, y, y_shape):
  - """Returns a node to compute gradient of x wrt y."""
  + """Returns a node to compute gradient of y wrt x."""
  # We make up a dy so that we can compute the gradients. We don't really use
  # the value of dy -- we will always feed it. We need to add an identity node
  # so that we can always feed it properly. Otherwise, for the Add operation,
  @@ -189,7 +189,7 @@ def _compute_dx_and_dy(x, y, y_shape):
  with x.graph.as_default():
  dy_orig = constant_op.constant(1.0, shape=y_shape, dtype=y.dtype)
  dy = array_ops.identity(dy_orig)
  - # We compute the gradients for x wrt. y
  + # We compute the gradients for y wrt. x
  grads = gradients.gradients(y, x, dy)
  assert len(grads) == 1
  return grads[0], dy_orig
  