Don't mark container-selinux as legacy Docker package anymore on CentOS

Summary:
To replace the legacy docker (<1.12) package by modern docker-ce/docker-ee packages,
the docker-common, docker-selinux and docker-engine packages has been correctly
removed.

Yet, the formerly removed container-selinux package has now been reintroduced
as a dependency of docker-ce-selinux.

This is a follow-up of b2d950dd11a7.

Test Plan: Checked on Dwellers

Reviewers: dereckson

Reviewed By: dereckson

Differential Revision: https://devcentral.nasqueron.org/D1378