hg_access_spec.rb is way too slow
About 13 minutes on my development workstation!
This test file is almost a duplication of
git_access_spec.rb, and that is intentional.
It's probably doing over and over something that's fast with Git and slow with Mercurial, like creating and recreating repositories over and over. This test shouldn't even need a real repository, we have good chances to make progress on this.