homed: rescan /home/ in more occasions automatically

homed: rescan /home/ in more occasions automatically

When unregistering a home there's a chance this "reveals" another home
by the same name in /home/, hence immediately schedule a rescan, the
same way we already schedule it in on remove.

Also, drop the conditionalization when scheduling a rescan during
remove, for the same reasons: a remove might reveal another home, and we
cannot check for that ahead of time. Trying to check is kinda a
pointless optimization anyway, since this is not a frequent operation
and rescanning is not the end of the world.