Indent a forgoten line with 4 spaces.

git-svn-id: https://svn.erp5.org/repos/neo/branches/prototype3@926 71dcc9de-d417-0410-9af5-da40c76e7ee4

neo/client/mq.py

@@ -72,7 +72,7 @@ class FIFO(object):
     def shift(self):
         element = self._head
         if element is None:
-          return None
+            return None
         del self[element]
         del element.next
         del element.prev