Completing the below X.org commit:

 commit a3a40291330bad10401fe2bcdbc097ce742b026a
 Author: Keith Packard <keithp@keithp.com>
 Date:   Mon Sep 21 07:16:16 2015 +0100

    os/xdmcp: Remove dead 'restart' code

    The X server used to wait for the user to hit a key or move the mouse
    before restarting the session after a keepalive failure. This,
    presumably, was to avoid having the X server continuously spew XDMCP
    protocol on the network while the XDM server was dead.

    Switching into this state was removed from the server some time before
    XFree86 4.3.99.16, so the remaining bits of code have been dead for
    over a decade, and no-one ever noticed.
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
Backported-to-NX-by: Mike Gabriel <mike.gabriel@das-netzwerkteam.de>