HDFS-6167. Relocate the non-public API classes in the hdfs.client package.


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HDFS-5591. Checkpointing should use monotonic time when calculating period. Contributed by Charles Lamb.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1583926 13f79535-47bb-0310-9956-ffa450edef68