Don't conflict with pulse

[jhamrick]

Ideally, gutenbach should work with pulse, because some people might want to run ubuntu-desktop, which depends on pulse. Despite Gutenbach being really only for servers, it would be nice to be as compatible as possible. The biggest problem right now is that pulse spews a whole bunch of errors like "Home directory var/spool/cups/tmp not ours." I can't figure out how to get rid of them, but they're really annoying. As long as pulse is in system mode, things seem to work otherwise.)