add method to get directly roles for a user

git-svn-id: https://svn.apache.org/repos/asf/archiva/redback/redback-core/trunk@1433392 13f79535-47bb-0310-9956-ffa450edef68
use new method

git-svn-id: https://svn.apache.org/repos/asf/archiva/redback/redback-core/trunk@1433394 13f79535-47bb-0310-9956-ffa450edef68