HBASE-9921 stripe compaction - findbugs and javadoc issues, some improvements

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1540215 13f79535-47bb-0310-9956-ffa450edef68
HBASE-9890 MR jobs are not working if started by a delegated user

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1540242 13f79535-47bb-0310-9956-ffa450edef68