Git commits in Moodle 3.4.1 by David Knuplesch

commit 4a2bc331fbc5f9cfb85becda7b94a668e1453609
Author: David Knuplesch <david.knuplesch@uni-ulm.de>
Date:   Tue, 12 Dec 2017 18:44:44 +0800
Tag:    v3.4.1

MDL-60415 mod_lti: avoid confusing error-message