fix cache invalidate when deleting a groupId

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1583868 13f79535-47bb-0310-9956-ffa450edef68
invalidate namespace cache when deleting a repository

git-svn-id: https://svn.apache.org/repos/asf/archiva/trunk@1583869 13f79535-47bb-0310-9956-ffa450edef68