pkg/ovn: object-ify gressPolicy and portPolicy
pkg/ovn: object-ify gressPolicy and portPolicy

Signed-off-by: Dan Williams <aeade43d0f8ae14e7c44fa81fe17c1635ae376fe@redhat.com>

shettyg/ovn-kubernetes,shettyg/ovn-kubernetes,shettyg/ovn-kubernetes