[gimp] Add licence comments to AppData file.

[Sven Claussner <sclaussner src gnome org>]

commit ef21616535f34701272244aac2d0e71f20dd528d
Author: Sven Claussner <sclaussner src gnome org>
Date:   Fri Sep 20 20:56:19 2013 +0200

    Add licence comments to AppData file.
    
    Explain the meaning of the licence tag and
    the GPL compatibility of the used CC0 licence.
    (cherry picked from commit ebef7983e8fbfab2d6c0bec266ae09e2f91e8a54)

 desktop/gimp.appdata.xml |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/desktop/gimp.appdata.xml b/desktop/gimp.appdata.xml
index 0286af2..276cc0e 100644
--- a/desktop/gimp.appdata.xml
+++ b/desktop/gimp.appdata.xml
@@ -1,6 +1,13 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <application>
 <id type="desktop">gimp.desktop</id>
+<!--
+The tag 'licence' means the licence of this file, not the whole product;
+see http://people.freedesktop.org/~hughsient/appdata/ as of 20.09.2013.
+The CC0 licence is GPL compatible, see 
+http://www.gnu.org/licenses/license-list.html#GPLCompatibleLicenses
+as of 20.09.2013
+-->
 <licence>CC0</licence>
 <description>
 <p>