Comment 4 for bug 509168

I already use launchpadlib with xdg, mostly I simply specify the cache dir. see here: http://bazaar.launchpad.net/~doctormo/groundcontrol/trunk/annotate/head%3A/GroundControl/launchpad.py

Although my code uses a friendly xdg wrapper called xdgapp.py it should be easy to see what it's doing.