Author: Paul Holden
MDL-80344 calendar: correct no subscriptions language string use.
Ensure expected parameters are present; avoid string concatenation.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=f537f9c067b4183e01654ba43e116dfe2fa82a79
http://github.com/moodle/moodle/commit/f537f9c067b4183e01654ba43e116dfe2fa82a79
+ 4.3 en [nocalendarsubscriptionsimportexternal,core_calendar]