Author: David Mudrák
MDL-49329 admin: Require confirmation before cancelling plugin install
http://git.moodle.org/gw?p=moodle.git;a=commit;h=4d7528f9bc33955ef6c2db07c212a4ad010edd1e
http://github.com/moodle/moodle/commit/4d7528f9bc33955ef6c2db07c212a4ad010edd1e
+ 3.0 en [cancelinstallhead,core_plugin]
+ 3.0 en [cancelinstallinfo,core_plugin]
+ 3.0 en [cancelinstallinfodir,core_plugin]