Author: John Okely
MDL-53988 mod_lti: Add language string for unactivated proxies
http://git.moodle.org/gw?p=moodle.git;a=commit;h=b1c8a860cbb51f8d6b3115d9f16190692c56a8fb
http://github.com/moodle/moodle/commit/b1c8a860cbb51f8d6b3115d9f16190692c56a8fb
+ 3.1 en [activatetoadddescription,mod_lti]