packaging: use full PyPI URL for RPM Source tarball
packaging: use full PyPI URL for RPM Source tarball

Alfredo has published the radosgw-agent package to PyPI today. Add the
full URL.

Signed-off-by: Ken Dreyer <940dddfbf8b0685439b7ecf27daa0ba58b359a2c@redhat.com>

ceph/radosgw-agent,ceph/radosgw-agent