HDFS-4259. Improve pipeline DN replacement failure message. Contributed by Harsh J. (harsh)

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HADOOP-9241. DU refresh interval is not configurable. Contributed by Harsh J. (harsh)

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HADOOP-9247. Merge r1438698 from trunk

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HDFS-4444. Mrege 1439559 from trunk.

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Reverting MAPREDUCE-2264

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merge MAPREDUCE-4803 from trunk. Remove duplicate copy of TestIndexCache. Contributed by Mariappan Asokan


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HADOOP-9255. relnotes.py missing last jira (tgraves)

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