MAPREDUCE-3757. [Rumen] Fixed Rumen Folder to adjust shuffleFinished and sortFinished times when needed. (Ravi Gummadi via tgraves)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1461296 13f79535-47bb-0310-9956-ffa450edef68