[geary] Ensure gnome-control-centre knows in advance Geary uses notifications.

[Michael Gratton <mjog src gnome org>]

commit 66648a6a945de53cc00daddcbe1de98a39490465
Author: Michael James Gratton <mike vee net>
Date:   Thu Jan 11 03:22:55 2018 +1100

    Ensure gnome-control-centre knows in advance Geary uses notifications.
    
    * desktop/org.gnome.Geary.desktop.in: Add X-GNOME-UsesNotifications=true
      to desktop file per:
      https://wiki.gnome.org/Initiatives/GnomeGoals/NotificationSource

 desktop/org.gnome.Geary.desktop.in |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/desktop/org.gnome.Geary.desktop.in b/desktop/org.gnome.Geary.desktop.in
index 0efff68..8a8f838 100644
--- a/desktop/org.gnome.Geary.desktop.in
+++ b/desktop/org.gnome.Geary.desktop.in
@@ -13,6 +13,7 @@ Terminal=false
 Categories=GNOME;GTK;Network;Email;
 MimeType=x-scheme-handler/mailto;
 StartupNotify=true
+X-GNOME-UsesNotifications=true
 Actions=Compose;
 
 [Desktop Action Compose]