Legacy support - old bodhi messages don't have this field.
Legacy support - old bodhi messages don't have this field.

This is so that we can still process old entires in datanommer.

Ghost-script/fedmsg_meta_fedora_infrastructure,fedora-infra/fedmsg_meta_fedora_infrastructure,sayanchowdhury/fedmsg_meta_fedora_infrastructure,opoplawski/fedmsg_meta_fedora_infrastructure