HBASE-8622 Remove ' You are currently running the HMaster without HDFS append support enabled. This may result in data loss. Please see the HBase wiki for details. ' from UI

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1486346 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk-gd
Merge remote branch 'origin/trunk-gd' into fb-HBASE-8559-trunk-gd