HBASE-9861 Location does not have to be refreshed on regionTooBusy

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.96@1537426 13f79535-47bb-0310-9956-ffa450edef68
HBASE-9862 manage error per server and per region in the protobuffed client

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.96@1537432 13f79535-47bb-0310-9956-ffa450edef68
HBASE-8556 fix coverage org.apache.hadoop.hbase.metrics.histogram (Aleksey Gorshkov)

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