[PATCH xserver] glx: Don't pass NULL to glxGetClient

[Adam Jackson]

On Mon, 2018-02-26 at 17:30 +0100, Michel Dänzer wrote:
> From: Michel Dänzer <michel.daenzer at amd.com>
> 
> These guards were dropped by the commit below, but it turns out they're
> needed. Fixes crash on VT switch.

Mea culpa. I think this snuck in as part of an attempt on my part to
get rid of the current client list that didn't quite get finished.

Merged, thanks:

remote: I: patch #206835 updated using rev 22a3ffe68c9c498e0b6b74ebcf1404becda8e2b1.
remote: I: 1 patch(es) updated to state Accepted.
To ssh://git.freedesktop.org/git/xorg/xserver
   528c94c650..22a3ffe68c  master -> master

- ajax