kiji-mapreduce: KIJIMR-282. Add constants to JobHistoryKijiTable for job success and failure messages

issue: https://jira.kiji.org/browse/KIJIMR-282
review: https://review.kiji.org/r/1892
commit: https://github.com/kijiproject/kiji-mapreduce/commit/10781ad8c06847d23bc6d954e93f87ac040a8fbd