message: Change topk error message to say how many columns existed and how many were requested.
diff: @@ -64,7 +64,9 @@ class TopK : public OpKernel {
  errors::InvalidArgument("input must be >= 1-D, got shape ",
  input_in.shape().DebugString()));
  OP_REQUIRES(context, input_in.dim_size(input_in.dims() - 1) >= k,
  - errors::InvalidArgument("input must have at least k columns"));
  + errors::InvalidArgument(
  + "input must have at least k columns. Had ",
  + input_in.dim_size(input_in.dims() - 1), ", needed ", k));
  const auto& input = input_in.flat_inner_dims<T>();
  