Added notify to systemd on startup

This doesn't fix any bugs by itself. This just adds feedback to systemd so that it knows when ofono has really been started. Later, if needed, we can add control to other daemons if they need to be started after ofono by editing their .service file and adding line "After=ofono.service"

Signed-off-by: Pekka Lundstrom <pekka.lundstrom@jollamobile.com>