grass.appdata.xml: fix id tag by adding .desktop

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@72184 15284696-431f-4ddb-bdfa-cd5b030d7da7

gui/icons/grass.appdata.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!-- Copyright 2014 Richard Hughes <richard@hughsie.com> -->
 <component type="desktop">
-  <id>org.osgeo.grass</id>
+  <id>org.osgeo.grass.desktop</id>
   <name>GRASS GIS</name>
   <metadata_license>CC0-1.0</metadata_license>
   <project_license>GPL-2.0+</project_license>