Git commits in Moodle 3.1.x by Vladimir Zhirov

commit ac47ed92fbb96581eaebae0892546244de846d91
Author: Vladimir Zhirov <vvzh@users.noreply.github.com>
Date:   Sun, 27 Nov 2016 03:42:54 +0800
Tag:    v3.1.4

MDL-57163 installation: fixed "Call to undefined function curl_version"