HADOOP-10029. Merging change 1531125 from trunk.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1531126 13f79535-47bb-0310-9956-ffa450edef68
YARN-1265. Fair Scheduler chokes on unhealthy node reconnect (Sandy Ryza)

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HDFS-5335. Merge 1531152 from trunk

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HADOOP-10039. Merge change r1531158 from trunk.

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