change dep for docker-selinux in centos-7+
change dep for docker-selinux in centos-7+

Use the policy files provided by CentOS for docker by depending on
docker-selinux.

Signed-off-by: Andrew Hsu <f92968afc12903b4e22dfb0d2a8d9823100da266@docker.com>

medallia/docker,medallia/docker,stainboy/docker,medallia/docker,stainboy/docker,stainboy/docker,medallia/docker