Code review comment for lp://qastaging/~xnox/ubuntu-release-upgrader/lp1409555

Hi Dimitri, thanks a lot for this work. The branch looks good, whats puzzling is that I see a test failure when running bzr-buildpackage. It looks like nosetests3 is not using the current directory and not honoring PYTHONPATH here which is a bit confusing. Only when python3-distupgrade is not instaleld do the tests work for me when run with nosetest3. Beside this the diff looks fine and I think we should upload it.