[gnome-shell] build: Update gvc subproject

[Florian Müllner <fmuellner src gnome org>]

commit 2aceeac7e0e5ddd1deddb35e6bc24265ccdc1465
Author: Florian Müllner <fmuellner gnome org>
Date:   Thu Jul 20 01:28:35 2017 +0200

    build: Update gvc subproject

 subprojects/gvc |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/subprojects/gvc b/subprojects/gvc
index 01e1fde..3f71aac 160000
--- a/subprojects/gvc
+++ b/subprojects/gvc
@@ -1 +1 @@
-Subproject commit 01e1fde6e5cc416d4fe7b1d8a7afb97455210e3a
+Subproject commit 3f71aac04ba98c4fef815c3a23b00a9eec02ca4d