make it working with recent maven core version

git-svn-id: https://svn.apache.org/repos/asf/maven/skins/trunk@1546502 13f79535-47bb-0310-9956-ffa450edef68
make it working with recent maven core version

git-svn-id: https://svn.apache.org/repos/asf/maven/skins/trunk@1546503 13f79535-47bb-0310-9956-ffa450edef68