kiji-mapreduce: KIJIMR-254. Update build script with artifact qualifier.

issue: https://jira.kiji.org/browse/KIJIMR-254
review: https://review.kiji.org/r/1463
commit: https://github.com/kijiproject/kiji-mapreduce/commit/0895e25b7566e8eccbe221d4ea06077b94bdd7b7