Git commits in Moodle 3.6.3 by Jean-Michel Vedrine

commit 5f9d6e34a3fa4c39b1236be1fdbfebfc1be92581
Author: Jean-Michel Vedrine <vedrine@vedrine.org>
Date:   Tue, 19 Feb 2019 00:48:32 +0800
Tag:    v3.6.3

MDL-63905 qtype_multianswer: validate imported questions