MAPREDUCE-5596. Allow configuring the number of threads used to serve shuffle connections. Contributed by Sandy Ryza


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1536711 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-5598. TestUserDefinedCounters.testMapReduceJob is flakey. Contributed by Robert Kanter


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1536724 13f79535-47bb-0310-9956-ffa450edef68