[services] Drop xbmcloaded "service".

**Needs xbianonpi/xbian-package-upstart-xbmc-bridge#5 merged.**

This was moved to the "Upstart bridge" add-on with commit
anaconda/xbian-package-upstart-xbmc-bridge@03d4ebbcfb8a6f0d873bd14fa8aaec241913c6cd. That's indeed the right place to manage Upstart things.