Fix Xorg abort on exit in RHEL 7.7+

RHEL adds an extra LeaveVT calls to xf86CrtcCloseScreen when they build X server
for the purpose to drop drm master.

Signed-off-by: Slava Grigorev <slava.grigorev@amd.com>
12 jobs for master in 11 minutes and 42 seconds (queued for 11 seconds)
latest
Status Job ID Name Coverage
  Docker Image
passed #593523
debian-testing

00:09:31

 
  Build
passed #593526
xserver-1.13

00:00:39

passed #593527
xserver-1.14

00:00:32

passed #593528
xserver-1.15

00:00:30

passed #593529
xserver-1.16

00:00:35

passed #593530
xserver-1.17

00:00:35

passed #593531
xserver-1.18

00:00:31

passed #593532
xserver-1.18-clang

00:00:53

passed #593533
xserver-1.19

00:00:30

passed #593534
xserver-1.19-clang

00:00:34

passed #593524
xserver-1.20

00:00:56

passed #593525
xserver-1.20-clang

00:00:51