Git commits in Moodle 3.1.0 by Fred Woolard

commit 1ac585fefd5f78548c18796ee43f9306a671fcec
Author: Fred Woolard <woolardfa@appstate.edu>
Date:   Wed, 06 Apr 2016 04:29:32 +0800
Tag:    v3.1.0-rc1

MDL-53713 core: account for session_start returning false