YARN-1521. Mark Idempotent/AtMostOnce annotations to the APIs in ApplicationClientProtcol, ResourceManagerAdministrationProtocol and ResourceTrackerProtocol so that they work in HA scenario. Contributed by Xuan Gong

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1581678 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5910. Enhance DataTransferProtocol to allow per-connection choice of encryption/plain-text. (Contributed by Benoy Antony)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1581688 13f79535-47bb-0310-9956-ffa450edef68
HDFS-6130. NPE when upgrading namenode from fsimages older than -32. Contributed by Haohui Mai.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1581713 13f79535-47bb-0310-9956-ffa450edef68