[gnome-2048] Use header bar in preferences window

[Juan R. Garcia Blanco <juanrgar src gnome org>]

commit 97082d29772993a39bfee1426d7df117a5c30891
Author: Juan R. García Blanco <juanrgar gmail com>
Date:   Sun Feb 22 21:56:39 2015 +0100

    Use header bar in preferences window

 data/preferences.ui |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/data/preferences.ui b/data/preferences.ui
index ea51853..faadf4c 100644
--- a/data/preferences.ui
+++ b/data/preferences.ui
@@ -16,6 +16,7 @@
     <property name="resizable">False</property>
     <property name="window_position">center-on-parent</property>
     <property name="type_hint">dialog</property>
+    <property name="use-header-bar">1</property>
     <child internal-child="vbox">
       <object class="GtkBox" id="dialog-vbox1">
         <property name="can_focus">False</property>