Git commits in Moodle 2.5.5 by Matt Petro

commit b095ee9f3aa8662a016e55c9cdd7d7abce6a4b72
Author: Matt Petro <petro@engr.wisc.edu>
Date:   Fri, 07 Feb 2014 02:32:04 +0800
Tag:    v2.5.5

MDL-44029 mod_quiz: Fixing group deleted handler so it does not remove user overrides.