HBASE-10315 Canary shouldn't exit with 3 if there is no master running.

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.96@1557866 13f79535-47bb-0310-9956-ffa450edef68
HBASE-10274 MiniZookeeperCluster should close ZKDatabase when shutdown ZooKeeperServers (chendihao via enis)

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.96@1557921 13f79535-47bb-0310-9956-ffa450edef68
HBASE-10320 Avoid ArrayList.iterator() ExplicitColumnTracker

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