OAK-942: document diff wrt permissions

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1572194 13f79535-47bb-0310-9956-ffa450edef68
building documentation is broken

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1572195 13f79535-47bb-0310-9956-ffa450edef68