[gitg] Enable vala support for libgit2-glib

[Jesse van den Kieboom <jessevdk src gnome org>]

commit f9ba8d8c77c97cee5f9e76296f10be1b08ce6037
Author: Jesse van den Kieboom <jessevdk gnome org>
Date:   Wed Dec 30 13:07:45 2015 +0100

    Enable vala support for libgit2-glib

 osx/Taps/gitg/gitg.rb |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/osx/Taps/gitg/gitg.rb b/osx/Taps/gitg/gitg.rb
index f6030a9..2227d37 100644
--- a/osx/Taps/gitg/gitg.rb
+++ b/osx/Taps/gitg/gitg.rb
@@ -20,7 +20,7 @@ class Gitg < Formula
   depends_on "gnome/gitg/gtkspell3"
   depends_on "gnome/gitg/libgee"
   depends_on "gnome/gitg/gsettings-desktop-schemas"
-  depends_on "gnome/gitg/libgit2-glib"
+  depends_on "gnome/gitg/libgit2-glib" => "with-vala"
   depends_on "gnome/gitg/gnome-icon-theme"
 
   def install