Git commits in Moodle 3.1.x by Martin Gauk

commit 9de798de718786ba40428682e36632346d38bb34
Author: Martin Gauk <gauk@math.tu-berlin.de>
Date:   Mon, 13 Mar 2017 20:49:14 +0800
Tag:    v3.1.6

MDL-58244 shibboleth: handle users who are logged out