py-git-sweep @0.1.1: not Python 3 compatible

[chrstphrchvz (Christopher Chavez)]

The upstream project is considered abandoned; no releases since the port was added in 2012. py27-git-sweep is the only remaining dependent of py27-gitpython (which is pinned to an older version). If a port for git-sweep should be kept, it ideally would work with Python 3. There have been multiple attempts to add Python 3 support to git-sweep, though I’m not aware which fork is considered most actively maintained and/or best for MacPorts to use.