fix license config on Java 6
fix license config on Java 6

blankazucenalg/lenskit,vaibhav345/lenskit,linjunleo/lenskit,vaibhav345/lenskit,aglne/lenskit,vaibhav345/lenskit,tajinder-txstate/lenskit,martinlaz/lenskit,kluver/lenskit,tajinder-txstate/lenskit,linjunleo/lenskit,vaibhav345/lenskit,tajinder-txstate/lenskit,amaliujia/lenskit,kluver/lenskit,tajinder-txstate/lenskit,binweiwu/lenskit,aglne/lenskit,martinlaz/lenskit,vijayvani/Lenskit,binweiwu/lenskit,chrysalag/lenskit,vijayvani/Lenskit,amaliujia/lenskit,blankazucenalg/lenskit,kluver/lenskit,kluver/lenskit,chrysalag/lenskit,kluver/lenskit