remove use of old httpunit library

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1555665 13f79535-47bb-0310-9956-ffa450edef68
refactor unit tests to get rid of the old httpunit

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1555666 13f79535-47bb-0310-9956-ffa450edef68
missed to add a class

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1555667 13f79535-47bb-0310-9956-ffa450edef68