Even though I thought this bug was somewhere in the TTY layer, it turns
out init(8) doesn't make sure /dev/console is opened initially properly.
I've added revoke() to two pieces of code:
- death(): Apart from killing the gettys on shutdown, this doesn't
guarantee the TTY to be closed immediately.
- runshutdown(): Just like setctty(), we should revoke /dev/console.
Applications like syslogd may have file descriptors to the console.
ced07ef3b3