Code review comment for lp://staging/~vila/bzr/646961-attr-error

So, I will consider that some tweaks being addressed I can land this for 2.2 and will follow-up with a submission against *trunk* for the others (report conflicts resolved and as_stanza).

I'll make yet another submission to *implement* --take-this/--take-other for text conflicts (but I'd like to also add --prefer-this/--prefer-other/--take-both for that and it's a bit more work).