Add AArch Xfce spin disk image

Signed-off-by: Paul Whalen <pwhalen@fedoraproject.org>

fedora.conf

@@ -421,6 +421,20 @@ image_build = {
                     'failable': ['*'],
                      }
         },
+        {
+            'image-build': {
+                    'format': [('raw-xz','raw.xz')],
+                    'name': 'Fedora-Xfce',
+                    'kickstart': 'fedora-disk-xfce.ks',
+                    'distro': 'Fedora-22',
+                    'disk_size': 7,
+                    'arches': ['aarch64'],
+                    'repo': 'Everything',
+                    'install_tree_from': 'Everything',
+                    'subvariant': 'Xfce',
+                    'failable': ['*'],
+                     }
+        },
         ],
     '^Workstation$': [
         {