Code review comment for lp:~takluyver/unattended-upgrades/py3

I think the nature of that test needs network communications - 'against real archive' seems to mean the Ubuntu package archive. I've disabled it so that "cd test/; make" doesn't see it (it checks the executable flag on the files). The package building doesn't appear to run any tests, however.

I've also dropped the backwards compatible imports, so it will only work with Python 3.