HBASE-10212 New rpc metric: number of active handler. (Chao Shi)

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1569122 13f79535-47bb-0310-9956-ffa450edef68
HBASE-10555 Backport HBASE-8519 to 0.94, Backup master will never come up if primary master dies during initialization (Jingcheng Du, original patch by Jerry He)

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1569123 13f79535-47bb-0310-9956-ffa450edef68
HBASE-10552 HFilePerformanceEvaluation.GaussianRandomReadBenchmark fails sometimes.

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1569129 13f79535-47bb-0310-9956-ffa450edef68
HBASE-10562 Fix TestMultiTableInputFormat for Hadoop 2 in 0.94.

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1569165 13f79535-47bb-0310-9956-ffa450edef68