Author: Nathan Nguyen
MDL-68702 core_backup: exclude legacy course files
http://git.moodle.org/gw?p=moodle.git;a=commit;h=65c847d8fd6ea98caafbfcbba1638cf39448377e
http://github.com/moodle/moodle/commit/65c847d8fd6ea98caafbfcbba1638cf39448377e
+ 4.0 en [configlegacyfiles,core_backup]
+ 4.0 en [generallegacyfiles,core_backup]
+ 4.0 en [rootsettinglegacyfiles,core_backup]