back to use wagon for remote download index to prevent unit test failure

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1541818 13f79535-47bb-0310-9956-ffa450edef68
dependency not anymore needed

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1541819 13f79535-47bb-0310-9956-ffa450edef68