MAPREDUCE-5787. Added the ability to keep alive shuffle connections in the MapReduce shuffle-handler. Contributed by Rajesh Balamohan.
svn merge --ignore-ancestry -c 1580062 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.4@1580064 13f79535-47bb-0310-9956-ffa450edef68