Hard code freeze break request for gnome-desktop

[Giovanni Campagna <scampa giovanni gmail com>]

Hello release-team,

This time I'd like to request a freeze break for
https://bugzilla.gnome.org/show_bug.cgi?id=708284.

The bug is about gnome-desktop (and components using it, such as
gnome-settings-daemon) noticing that mutter was restarted, for example
due to a crash or alt-f2 r.
Without the patch, all gnome-rr operations from gnome-settings-daemon
(which are primarily blanking the screen, applying the correct gamma
and setting the brightness) would fail with AccessDenied if there were
screen reconfigurations between when gnome-settings-daemon started and
when mutter restarted. It is an edge case, in a sense, but it becomes
very common in a developer environment.

Thanks for your time as always, and cheers,

Giovanni