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

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1537425 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/trunk@1537431 13f79535-47bb-0310-9956-ffa450edef68
HBASE-8556 fix coverage org.apache.hadoop.hbase.metrics.histogram (Aleksey Gorshkov)

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1537436 13f79535-47bb-0310-9956-ffa450edef68