[gnome-shell] Restore gvc submodule

[Florian Müllner <fmuellner src gnome org>]

commit 373ebb50eb93d3447974c2959de2f0f548ed3f61
Author: Florian Müllner <fmuellner gnome org>
Date:   Sun Sep 11 19:19:33 2016 +0200

    Restore gvc submodule
    
    Commit 68f439425bd accidentally dropped the changes from the last
    couple of months ...

 src/gvc |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/gvc b/src/gvc
index 0a79019..25bf3ed 160000
--- a/src/gvc
+++ b/src/gvc
@@ -1 +1 @@
-Subproject commit 0a79019088ce2f50b671c7964b8fd69c24a465b9
+Subproject commit 25bf3ed75fa604fa73e8b25241119a993fc659d6