FIX: Spotlight: searching in user homes, bug #543

Spotlight cannot search in user homes.
When netatalk(8) starts, it sets up paths for Spotlight.
Since user has not logged in yet, nobody sets up home's path.
Can we avoid calling **tracker-control -s** for every home mount? This should probably be moved to etc/netatalk/netatalk.c or something similar that ensures we only call out to tracker-control once in order to start it up.