Git commits in Moodle 2.6.4 by Jean-Michel Vedrine

commit 4fb94f7f96db3e10c52d06ad63ab6ef42ca2e316
Author: Jean-Michel Vedrine <vedrine@vedrine.org>
Date:   Sat, 24 May 2014 05:08:36 +0800
Tag:    v2.6.4

MDL-45686 qtype_multichoice get_num_selected_choices return wrong result