Merge -r 1448601:1448602 from trunk to branch-2. Fixes: MAPREDUCE-5013. mapred.JobStatus compatibility: MR2 missing constructors from MR1. Contributed by Sandy Ryza.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1448604 13f79535-47bb-0310-9956-ffa450edef68