be consistent for index repository created with a relative path with default ones

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1443219 13f79535-47bb-0310-9956-ffa450edef68
remove duplicate code with using exposed method

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1443220 13f79535-47bb-0310-9956-ffa450edef68