svn merge -c -1430507 . for reverting HDFS-4353. Encapsulate connections to peers in Peer and PeerServer classes


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1430662 13f79535-47bb-0310-9956-ffa450edef68
svn merge -c -1428729 . for reverting HDFS-4352. Encapsulate arguments to BlockReaderFactory in a class


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1430663 13f79535-47bb-0310-9956-ffa450edef68