Author: Andrew Davis
MDL-48894 core_registration: minor string tweak
http://git.moodle.org/gw?p=moodle.git;a=commit;h=fe391a4e0ca1ffb21b894834b22d83ecd4bc40d9
http://github.com/moodle/moodle/commit/fe391a4e0ca1ffb21b894834b22d83ecd4bc40d9
+ 2.9 en [pleaserefreshregistrationunknown,core_admin]