MAPREDUCE-5952. LocalContainerLauncher#renameMapOutputForReduce incorrectly assumes a single dir for mapOutIndex. (Gera Shegalov via kasha)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1611197 13f79535-47bb-0310-9956-ffa450edef68