Comment # 10 on bug 947734 from Dr. Werner Fink

This is a bug of X11 and not of systemd.  X11 is not able to handle a restart
of the logind ... compare with bug #934901

Could we get a *working* X11 here?  Disabling the restart of logind is only a
*workaround* as X11 should be able to re-attach.