kiji-scoring-server: SCORSRVR-5. Update to work with ModelContainer

issue: https://jira.kiji.org/browse/SCORSRVR-5
review: https://review.kiji.org/r/1635
commit: https://github.com/kijiproject/kiji-scoring-server/commit/864722288a03e85f4a7fac116fa020ad4c5dcf09