Comment 3 for bug 917057

Alright, I know what part of this is. On Arch Linux, /usr/bin/python is a symlink to python3. On most other Linuxes I've seen, it's been a symlink to a version of python2.

This causes the mock duplicity script used in the tests to fail (written for python2, but is run under python3). I can workaround this by just porting the script to python3 (a good thing to do anyway). Then I hit another error, which I'm looking into.