MAPREDUCE-5317. Stale files left behind for failed jobs. Contributed by Ravi Prakash


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1506154 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-5356. Ability to refresh aggregated log retention period and check interval. Contributed by Ashwin Shankar


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1506226 13f79535-47bb-0310-9956-ffa450edef68