This patch is not necessary at the current code level. But when xkb
code introduced the dev->key check Xorg upstream missed that. So we
backport it now to skip that trap when updating xkb code.

  Author: Alan Coopersmith <alan.coopersmith@sun.com>
  Date:   Mon Jan 4 18:21:54 2010 -0800

    CloseDevice: call XkbRemoveResourceClient before freeing key class struct

    XkbRemoveResourceClient() returns immediately if dev->key is NULL.
    CloseDevice calls XkbRemoveResourceClient until it removes all resources.

    If we free dev->key and NULL it before XkbRemoveResourceClient, then
    infinite loop ensues, and the server appears to hang on exit or crash.
Signed-off-by: Alan Coopersmith <alan.coopersmith@sun.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Daniel Stone <daniel@fooishbar.org>
Signed-off-by: Keith Packard <keithp@keithp.com>
Backported-to-NX-by: Ulrich Sibiller <uli42@gmx.de>