HDFS-3429. DataNode reads checksums even if client does not need them. Contributed by Todd Lipcon.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1433117 13f79535-47bb-0310-9956-ffa450edef68
YARN-330. Fix flakey test: TestNodeManagerShutdown#testKillContainersOnShutdown. Contributed by Sandy Ryza

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1433138 13f79535-47bb-0310-9956-ffa450edef68
HDFS-4364. GetLinkTargetResponseProto does not handle null path. Contributed by Suresh Srinivas.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1433194 13f79535-47bb-0310-9956-ffa450edef68
HDFS-4369. GetBlockKeysResponseProto does not handle null response. Contributed by Suresh Srinivas.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1433206 13f79535-47bb-0310-9956-ffa450edef68