- display a message that all applications should be closed for the 
  dist-upgrade (and that strange things like a crashing panel can
  happen)
- stop gnome-volume-manager before the hoary->breezy upgrade
  (it will crash otherwise)
- DistUpgradeControler.sanityCheck:
  * fix borken caches
  * check for ubuntu desktop etc
- check authentication and don't upgrade anything that is not
  authenticated (maybe just comment unauthenticated stuff out?)