vc-git-annotate vs configured date format

[Karl Chen]

I have this in my .gitconfig:
    [blame]
            date = short

Which causes emacs' vc-annotate to not work correctly, because
vc-git-annotate-time hardcodes the regexp it looks for assuming
it's date=iso.

What do you think about getting vc-git-annotate to work regardless
of the blame.date setting?

An easy fix would be to just add --date=iso to the command-line.
But ideally Emacs would be able to parse other date formats also.
Date=short would be pretty easy to check for since it's a subset
of date=iso; others might be harder.

Thanks,
Karl