HDFS-5366. recaching improvements (cmccabe)

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HDFS-5440. Extract the logic of handling delegation tokens in HftpFileSystem to the TokenAspect class. Contributed by Haohui Mai.

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HADOOP-9594 commons-math

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MAPREDUCE-5431 Missing pom dependency in MR-client

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Merge remote branch 'origin/trunk' into trunk-gd