Code review comment for lp:~submarine/ubuntu-scopes/colourlovers-set-as-wallpaper

I had a look at this and pushed a fix to use mkdtemp(): it looks like the Python 3 version of nosetests is eating the exception due to some Python 2.x baggage, which made the cause a little less obvious. I also stubbed out the gsettings code so it should function in the testing environment.