HBASE-8008: Fix DirFilter usage to be consistent

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1453465 13f79535-47bb-0310-9956-ffa450edef68
HBASE-8006 use FSUtils to get/set hbase.rootdir

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1453521 13f79535-47bb-0310-9956-ffa450edef68