[gnome-control-center] flatpak: add meson build system to gnome-desktop

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 5912de10e4a40c844518b2eaed46dab735af2e83
Author: RyuzakiKK <aasonykk gmail com>
Date:   Mon Sep 17 20:32:31 2018 +0200

    flatpak: add meson build system to gnome-desktop

 build-aux/flatpak/org.gnome.Settings.json | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/build-aux/flatpak/org.gnome.Settings.json b/build-aux/flatpak/org.gnome.Settings.json
index d440b6a42..2c1798958 100644
--- a/build-aux/flatpak/org.gnome.Settings.json
+++ b/build-aux/flatpak/org.gnome.Settings.json
@@ -254,6 +254,7 @@
         },
         {
             "name" : "gnome-desktop",
+            "buildsystem" : "meson",
             "sources" : [
                 {
                     "type" : "git",