HBASE-8426 Opening a region failed on Metrics source RegionServer,sub=Regions already exists

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1477247 13f79535-47bb-0310-9956-ffa450edef68
HBASE-8407 Remove Async HBase

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1477251 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk-gd