Clean up prepare_tty()
Clean up prepare_tty()

When TTYs became first class citizens in Finit 4.0 much of the
boilerplate setup is now down by service_start().  Also, the calls to
TIOCSCTTY, VINTR, and SIGINT ignore is not necessary to do here, it
should be done by the getty used, if any.

Signed-off-by: Joachim Wiberg <583c295fd7602c168ad814279bbc3894ba65f5d6@gmail.com>

troglobit/finit,troglobit/finit