Description of problem:
When I enable 'Auto resize VM with window' option in my virtmanager, the VM is flickering and is basically unusable. At the same time, I can see a lot of messages in my journal:

```
Sep 20 08:17:34 unused-4-175.brq.redhat.com kernel: input: spice vdagent tablet as /devices/virtual/input/input13
Sep 20 08:17:34 unused-4-175.brq.redhat.com gnome-shell[1106]: Could not release device 13,69: GDBus.Error:org.freedesktop.login1.DeviceNotTaken: Device not taken
Sep 20 08:17:34 unused-4-175.brq.redhat.com gnome-settings-[1358]: unable to get EDID for xrandr-Virtual-1: unable to get EDID for output
Sep 20 08:17:35 unused-4-175.brq.redhat.com gnome-settings-[1358]: unable to get EDID for xrandr-Virtual-1: unable to get EDID for output
Sep 20 08:17:36 unused-4-175.brq.redhat.com gnome-settings-[1358]: unable to get EDID for xrandr-Virtual-1: unable to get EDID for output
Sep 20 08:17:37 unused-4-175.brq.redhat.com gnome-settings-[1358]: unable to get EDID for xrandr-Virtual-1: unable to get EDID for output
```

It seems that the screen is flickering with the same frequency as this messages appear in the log.



Version-Release number of selected component (if applicable):
$ rpm -q spice-server 
spice-server-0.13.2-1.fc26.x86_64

$ rpm -q spice-vdagent 
spice-vdagent-0.16.0-3.fc24.x86_64

$ rpm -q gnome-settings-daemon 
gnome-settings-daemon-3.21.92.1-1.fc26.x86_64

$ uname -a
Linux unused-4-175.brq.redhat.com 4.8.0-0.rc6.git4.1.fc26.x86_64 #1 SMP Fri Sep 16 22:25:23 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux


How reproducible:


Steps to Reproduce:
1. Enable 'Auto resize VM with window' virt manager option.
2.
3.

Actual results:
The gnome-shell is flickering.


Expected results:
The gnome-shell is not flickering.


Additional info:
Disabling the 'auto resize' feature workaronds the issue.