Split halt.sh into halt, killprocs, romount and savecache services.
The reboot runlevel is removed but mapped to shutdown.
The halt script should be moved to the sysvinit package.
The runlevels shutdown, reboot, sysinit and single should be called by
init(8) and shutdown(8) and not manually.
sysvinit users will have to add sulogin to their inittab to secure the
console.
