Git commits in Moodle 3.3.6 by dinhloc

commit 5d70a00dd8bbc03526a25bc0c5cff2a31c8f991a
Author: dinhloc <ndloc1905@gmail.com>
Date:   Tue, 09 Jan 2018 10:38:54 +0800
Tag:    v3.3.6

MDL-61033 quiz: Editing a quiz while a preview is open