message: Make unsupported mask options clearer
diff: @@ -2127,10 +2127,10 @@ tensorflow::Status ConvertStridedSlice(OpConverterParams* params) {
  node_def.name());
  }
  }
  - // Unsupported options.
  + // Unsupported mask options.
  for (string attr : {"ellipsis_mask", "new_axis_mask", "shrink_axis_mask"}) {
  - int ellipsis_mask = attrs.get<int>(attr);
  - if (ellipsis_mask != 0) {
  + int attr_val = attrs.get<int>(attr);
  + if (attr_val != 0) {
  return tensorflow::errors::Unimplemented(
  attr, " is not implemented for StridedSlice, at ", node_def.name());
  }
  