Git commits in Moodle 2.3.x by David Penner

commit a0cc337bdb36b3bad144b34c2ec41df7f0438dbe
Author: David Penner <contributor@tracker.moodle.org>
Date:   Wed, 18 Jan 2012 11:19:27 +0800
Tag:    v2.3.0-beta

MDL-31160 block_navigation: Fixed incorrect thrid arg to substr.