fix wrong indent

since...

commit 6ec8387bea
Author: Caolán McNamara <caolanm@redhat.com>
Date:   Thu Jan 19 15:56:12 2017 +0000

    unbreak this wizard enough to run it

though in fairness it didn't work before that change anyway

Change-Id: Ibd454ec781c6a5ca65ad08f894854b556b046be6

wizards/com/sun/star/wizards/web/BackgroundsDialog.py

@@ -84,8 +84,8 @@ class BackgroundsDialog(ImageListDialog):
         while i < self.il.listModel.getSize():
             if self.il.listModel.getElementAt(i) == s:
                 return i
+            i += 1
 
-        i += 1
         self.il.listModel.add1(s)
         try:
             configView = Configuration.getConfigurationRoot(