Option --ctty will optionally add setsid binary to dracut's image.
During runtime, if rd.ctty is set and is a character device,
emergency shells will be spawned with job control.
in case no ctty was provided, shell was spawned without caring about
/dev/console. Also, the ctty is more opportunistic. If the image was
generated with --ctty, we will fallback to /dev/tty1 if rc.ctty is
invalid or missing. Otherwise we spawn standard shell on /dev/console
[dyoung@redhat.com: Rebased to usrmove branch]
Signed-off-by: Michal Soltys <soltys@ziu.info>
Signed-off-by: Dave Young <dyoung@redhat.com>