Git commits in Moodle 3.4.x by Viktor

commit b77dcd23d8e39265b5c096f0d947764c02d832c8
Author: Viktor <viktor.khokhryakov@gmail.com>
Date:   Mon, 04 Feb 2019 16:10:25 +0800
Tag:    v3.4.8

MDL-62702 core_lib: fix broken verification signature