[gnome-font-viewer] AppData: Mark as unremovable in GNOME Software

[Richard Hughes <rhughes src gnome org>]

commit 7911b324c2766596348470db18fb9a62a1821b1b
Author: Richard Hughes <richard hughsie com>
Date:   Mon Mar 28 16:23:55 2016 +0100

    AppData: Mark as unremovable in GNOME Software

 data/org.gnome.font-viewer.appdata.xml.in |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/data/org.gnome.font-viewer.appdata.xml.in b/data/org.gnome.font-viewer.appdata.xml.in
index 2467660..291b541 100644
--- a/data/org.gnome.font-viewer.appdata.xml.in
+++ b/data/org.gnome.font-viewer.appdata.xml.in
@@ -27,6 +27,7 @@
     </screenshot>
   </screenshots>
   <project_group>GNOME</project_group>
+  <compulsory_for_desktop>GNOME</compulsory_for_desktop>
   <kudos>
     <kudo>AppMenu</kudo>
     <kudo>ModernToolkit</kudo>