[gnome-builder] prefs: use EggCenteringBin

[Christian Hergert <chergert src gnome org>]

commit 5b3fdc43c7d34f0365eb568da15ed48be09cbc5e
Author: Christian Hergert <chergert redhat com>
Date:   Fri Nov 6 14:39:23 2015 -0800

    prefs: use EggCenteringBin

 data/ui/ide-preferences-page.ui |   17 +++++++++++------
 1 files changed, 11 insertions(+), 6 deletions(-)
---
diff --git a/data/ui/ide-preferences-page.ui b/data/ui/ide-preferences-page.ui
index 2c4269f..be8c39b 100644
--- a/data/ui/ide-preferences-page.ui
+++ b/data/ui/ide-preferences-page.ui
@@ -6,13 +6,18 @@
       <object class="GtkScrolledWindow">
         <property name="visible">true</property>
         <child>
-          <object class="GtkBox" id="box">
-            <property name="halign">center</property>
-            <property name="margin">24</property>
-            <property name="orientation">vertical</property>
-            <property name="spacing">24</property>
+          <object class="EggCenteringBin">
             <property name="visible">true</property>
-            <property name="width-request">500</property>
+            <child>
+              <object class="GtkBox" id="box">
+                <property name="halign">center</property>
+                <property name="margin">24</property>
+                <property name="orientation">vertical</property>
+                <property name="spacing">24</property>
+                <property name="visible">true</property>
+                <property name="width-request">500</property>
+              </object>
+            </child>
           </object>
         </child>
       </object>