Added plone.registry to auto-checkout, fixes regression caused by plone.supermodel fixes in https://github.com/plone/buildout.coredev/commit/b0abecb25aa18732208fcfb17b4ab172714d5c23 and https://github.com/plone/plone.supermodel/commit/f16f480b6062a44bda6f729f03de4555c65c82b0