svn merge -c 1541736 FIXES: HADOOP-9956. RPC listener inefficiently assigns connections to readers (daryn)


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svn merge -c 1541750 from trunk for HADOOP-10095. In CodecPool, synchronize pool and codecList separately in order to reduce lock contention.


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HDFS-5504. Merge change r1541773 from trunk.

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HDFS-5487. Merge change r1541776 from trunk.

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