This is currently copying everything into
https://tarballs.openstack.org/project-config/package-afs-centos7/x86_64/
where we don't actually want the "x86_64". Add trailing slash so it
copies the directory contents. Also remove any existing content with
--delete, we only want the latest.
Change-Id: I4b0fe994baaaf04db0fe552f88107d90e328f048