[pitivi] Install the 'stable' branch when running with the installer

[Thibault Saunier <tsaunier src gnome org>]

commit b63b068317dac36f8327e69291db186c0f371536
Author: Thibault Saunier <tsaunier gnome org>
Date:   Thu Jun 23 17:39:03 2016 -0400

    Install the 'stable' branch when running with the installer

 build/flatpak/pitivi-flatpak |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/build/flatpak/pitivi-flatpak b/build/flatpak/pitivi-flatpak
index 0dbb82f..d4ac0d3 100755
--- a/build/flatpak/pitivi-flatpak
+++ b/build/flatpak/pitivi-flatpak
@@ -144,6 +144,7 @@ do
     ;;
     --installer)
     INSTALLER=true
+    BRANCH="stable"
     shift
     ;;
     --use-remote)