Author: adrian@moodle.com
MDL-20627 user - Fixed viewing permission of email when sending group messages.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=97aef9b3ad08eeedc5bb4cd03bae4d004db6a854
http://github.com/moodle/moodle/commit/97aef9b3ad08eeedc5bb4cd03bae4d004db6a854
+ 2.1 en [emaildisplayhidden,core]