Small trivial annoyance with the nice new builtin "git am"

Ok, it's no longer *that* new, but I only now noticed..

So I noticed that when I applied the last patch-bomb series from
Andrew, all the commit date-stamps are idential.

Now, it would be lovely if the new builtin git-am really was *so* fast
that it applies a 100+-patch series in under a second, but no, that's
not it. It's just that it only looks up the current time once.

That seems entirely accidental, I think that what happened is that
"ident_default_date()" just ends up initializing the default date
string once, and then the date is cached there, because it's now run
as a single process for the whole series.

I think I'd rather get the "real" commit dates, even if they show that
git only does a handful of commits a second rather than hundreds of
commits..

Something that just clears git_default_date in between "git am"
iterations, perhaps?

                  Linus