[gnome-shell/gnome-3-8] Bump gvc submodule

[Florian Müllner <fmuellner src gnome org>]

commit 13bea1a01bf9fe2f4484c0f7e785b5ecec45266f
Author: Florian Müllner <fmuellner gnome org>
Date:   Fri May 31 20:50:42 2013 +0200

    Bump gvc submodule
    
    As of commit 95a1b874d8298, the submodule is supposed to be at
    revision 3d6aac673b88ff, but commit 31774a7711e72 accidentally
    reverted it back to the previously used revision.

 src/gvc |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/gvc b/src/gvc
index 03894ef..3d6aac6 160000
--- a/src/gvc
+++ b/src/gvc
@@ -1 +1 @@
-Subproject commit 03894efbcd010faf53bbc6e27256d27485f721b8
+Subproject commit 3d6aac673b88fff548db57a75b82e8f14723c1fe