fix default groupdn

git-svn-id: https://svn.apache.org/repos/asf/archiva/redback/redback-core/trunk@1430635 13f79535-47bb-0310-9956-ffa450edef68
fix get guest with ldap

git-svn-id: https://svn.apache.org/repos/asf/archiva/redback/redback-core/trunk@1430636 13f79535-47bb-0310-9956-ffa450edef68