Previously, we would include information about what git commit a build
came from in the "local" portion of the PEP-440 version. This was a
problem because PyPI does not allow packages to be upload to the
registry if they contain local parts.
So, for now, we'll just never put in the git commit information in the
generate version. We'll continue to add a dirty tag in the local
part. This will be prevent us from publishing dirty builds to PyPI,
but that's in line with what we want.
bb6b492d55