Git commits in Moodle 3.6.4 by Ilya Tregubov

commit a6b98fe71643263dbc44c57c435f7ac13968dee0
Author: Ilya Tregubov <ilyatregubov@catalyst-au.net>
Date:   Wed, 19 Dec 2018 10:21:04 +0800
Tag:    v3.6.4

MDL-64439 auth: Refresh $cm in require_login after pre_loginpage_hook.