[gnome-control-center] Fix grammar in a translators comment

[Piotr Drąg <piotrdrag src gnome org>]

commit bd4094d26e7cd59b98efa875cb1fdee8ad0663a6
Author: Piotr Drąg <piotrdrag gmail com>
Date:   Tue Feb 11 18:15:20 2014 +0100

    Fix grammar in a translators comment

 panels/background/background.ui |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/panels/background/background.ui b/panels/background/background.ui
index 91adfe7..59c9cf0 100644
--- a/panels/background/background.ui
+++ b/panels/background/background.ui
@@ -197,7 +197,7 @@
                           <object class="GtkLabel" id="label2">
                             <property name="visible">True</property>
                             <property name="can_focus">False</property>
-                            <property name="label" translatable="yes" comments="To translators: This is the 
noon, not the verb">Lock Screen</property>
+                            <property name="label" translatable="yes" comments="To translators: This is a 
noun, not a verb">Lock Screen</property>
                           </object>
                           <packing>
                             <property name="expand">False</property>