https://bugzilla.redhat.com/show_bug.cgi?id=1406517
--- Comment #4 from Jan Chaloupka jchaloup@redhat.com --- I don't think you need to make the constraint relative:
Obsoletes: docker-selinux <= %{epoch}:%{version}-28
It should be enough to fix it with some comment what is the docker-selinux obsoleted by the particular NEVR. E.g.
Obsoletes: docker-selinux <= 2:1.12.4-28