Author: David Mudrak
MDL-30271 Inform the user about the example assessment conflict, instead of throwing the exception
http://git.moodle.org/gw?p=moodle.git;a=commit;h=1b73e201c146d8df4a207aafbced079063db2dbd
http://github.com/moodle/moodle/commit/1b73e201c146d8df4a207aafbced079063db2dbd
+ 2.1 en [assessmentreferenceconflict,mod_workshop]