cmdutil: reimplement finddate() without using walkchangerevs()
It's simpler and slightly faster maybe because a fewer Python ops would
run.
Unscientific benchmark:
$ python -m timeit \ -s 'from mercurial import hg, ui, cmdutil; repo = hg.repository(ui.ui())' \ 'cmdutil.finddate(repo.ui, repo, "<2008-01-01")' (orig) 10 loops, best of 3: 1.45 sec per loop (new) 10 loops, best of 3: 1.25 sec per loop
Now "hg churn" and "hg grep" are the only users of walkchangerevs(), which
I want to refactor and fix bugs.