HADOOP-9688 merge r1500843 and r1500847, and HADOOP-9720 merge r1502301 from trunk

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Revert the merge r1505005

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HADOOP-9688 merge r1500843 and r1500847 from trunk.

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HADOOP-9691. Merge r1501615 from trunk.

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Revert r1505037 to fix the commit text

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HADOOP-9720 merge r1502301 from trunk.

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HADOOP-9691. Merge r1501615 from trunk.

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HADOOP-9716. Merge r1504362 from trunk.

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HADOOP-9717. Merge r1504725 from trunk.

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HADOOP-9751. Merge r1505036 from trunk.

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