Notification of string changes

Author: Tim Hunt
MDL-56136 restore: better error handling copying file at start


http://git.moodle.org/gw?p=moodle.git;a=commit;h=ff085ba20beeb851e43f4516e67009674b2412cb
http://github.com/moodle/moodle/commit/ff085ba20beeb851e43f4516e67009674b2412cb

+ 3.0 en [errorcopyingbackupfile,core_backup]