kiji-bento: BENTO-91. Update Bento Box to work with new KijiREST packaging (from REST-127)

issue: https://jira.kiji.org/browse/BENTO-91
review: https://review.kiji.org/r/1984
commit: https://github.com/kijiproject/kiji-bento/commit/9a3d35dace7ebeef8647703255c5ef18fcd63ea5