Author: Damyon Wiese
MDL-43334 backup: Lanuage for cancel
Cancel backup buttons need clear lang strings.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=ad83f25e94b67b92c6df5bbb25ea29f1602a1f5e
http://github.com/moodle/moodle/commit/ad83f25e94b67b92c6df5bbb25ea29f1602a1f5e
+ 3.4 en [confirmcancelyes,core_backup]
+ 3.4 en [confirmcancelno,core_backup]