Author: Arnaud Trouve
MDL-56547 admin : add check on user deletion
Check if the target user is not already deleted
and print an explicit error in that case.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=3009095bc97b55fd5659d0e9cd7f1aad0be00312
http://github.com/moodle/moodle/commit/3009095bc97b55fd5659d0e9cd7f1aad0be00312
+ 3.3 en [usernotdeleteddeleted,core_error]