[gnome-control-center] build: Bump required GTK+ version

[Yosef Or Boczko <yoseforb src gnome org>]

commit 635a4690865221a776ff869ecad0e5c358189f88
Author: Yosef Or Boczko <yoseforb gmail com>
Date:   Tue Nov 19 22:24:08 2013 +0200

    build: Bump required GTK+ version
    
    It's required for margin-start and margin-end.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=712661

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index cb69c19..4081e56 100644
--- a/configure.ac
+++ b/configure.ac
@@ -86,7 +86,7 @@ dnl Check that we meet the  dependencies
 dnl ==============================================
 
 GLIB_REQUIRED_VERSION=2.37.7
-GTK_REQUIRED_VERSION=3.9.12
+GTK_REQUIRED_VERSION=3.11.1
 PA_REQUIRED_VERSION=2.0
 CANBERRA_REQUIRED_VERSION=0.13
 GDKPIXBUF_REQUIRED_VERSION=2.23.0