HADOOP-10696. Add optional attributes to KeyProvider Options and Metadata. (tucu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1604041 13f79535-47bb-0310-9956-ffa450edef68
HDFS-6312. WebHdfs HA failover is broken on secure clusters. (daryn via tucu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1604045 13f79535-47bb-0310-9956-ffa450edef68
HDFS-6403. Add metrics for log warnings reported by JVM pauses. Contributed by Yongjun Zhang.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1604074 13f79535-47bb-0310-9956-ffa450edef68