Author: Petr Škoda
MDL-34046 improve mixed files upgrade error
Credit goes to Gordon Bateson.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=774c42a8d3d1df6f3e9cb1ab160d014f5ea9acbb
http://github.com/moodle/moodle/commit/774c42a8d3d1df6f3e9cb1ab160d014f5ea9acbb
+ 2.4 en [upgradestalefiles,core_admin]
+ 2.4 en [upgradestalefilesinfo,core_admin]