Code review comment for lp:~music-app-dev/music-app/use-mediascanner2.0

I left the patching/mocking/fakeenv code for the autopilot tests alone, but changed the setup path to no longer call it. Instead, the mediascanner, Music and music app database directories are now backed up at the start of the test and restored after completion. This is not ideal, but the mocking will require more apparmor policy work, so it is a stopgap for now.

Note, that should a test fail the restore might not work properly. Caveat emptor.