* mandos: Never call .Reset() on a defunct Avahi entry group. (AvahiService.remove): Only do group.Reset(), as before. (AvahiService.add): Only create new group if necessary. (AvahiService.cleanup): Also do group.Free() if a group exists. (AvahiService.server_state_changed): Call .cleanup() on errors. Also log error parameter, if passed.