Bug#769369: systemd: Can't restart or poweroff when X11 is active

[Nikolaus Rath]

More information:


* reboot -f and poweroff -f work fine.

* if I start a debug-shell on a serial port, at some point the shell
seems to freeze as well.

* if I boot with sysvinit (installing sysvinit-core instead of
systemd-sysv), things work fine:

  - The system reboots even if an X11 console is active
  - During the shutdown, I can switch between text consoles and see
    log messages


It seems that there is some problem with the way that X11 is terminated
when using systemd.