Ensure that the clobber task removes all the files generated by the build process

git-svn-id: https://svn.apache.org/repos/asf/buildr/trunk@1529582 13f79535-47bb-0310-9956-ffa450edef68
Record another release

git-svn-id: https://svn.apache.org/repos/asf/buildr/trunk@1529583 13f79535-47bb-0310-9956-ffa450edef68