[gnome-font-viewer] Revert "flatpak: use current commit by default"

[Cosimo Cecchi <cosimoc src gnome org>]

commit f3955cdbd681a1d9ee8eab69744fe5a2ff45236d
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Mon Sep 3 18:58:18 2018 -0700

    Revert "flatpak: use current commit by default"
    
    Does not seem to work as expected...
    
    This reverts commit 2540e7eeeb1c4316486fdd65ab5f353a25aae9c6

 flatpak/org.gnome.font-viewer.json | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
---
diff --git a/flatpak/org.gnome.font-viewer.json b/flatpak/org.gnome.font-viewer.json
index 4716c64..8949197 100644
--- a/flatpak/org.gnome.font-viewer.json
+++ b/flatpak/org.gnome.font-viewer.json
@@ -38,8 +38,7 @@
             "sources": [
                 {
                     "type": "git",
-                    "path": "..",
-                    "branch": "HEAD"
+                    "path": ".."
                }
             ]
         }