Git commits in Moodle 2.2.4 by Adam Olley

commit 66424a611f0ea8ac6f58f60483c716ca7d23b97e
Author: Adam Olley <adam.olley@netspot.com.au>
Date:   Tue, 28 Feb 2012 13:58:11 +0800
Tag:    v2.2.4

MDL-31802: Remove section summaries from navigation_cache