pypa/pip — pull request #636 by fabiocerqueira (2012-08-14 23:45:49+00:00)
Title: Fixed issue #609 - method to detect VCS backend

http://stackoverflow.com/questions/11935786/pip-freeze-reports-version-number-instead-of-git-sha-for-certain-package

After I saw this question I tried fix this, I don't know if is the best way, but now works ok.