containerd,docker: stop installing extras repo on CentOS/RHEL (#7203)

This was introduced in 143e2272ff
Extra repo is enabled by default in CentOS, and is not the right repo for EL8
Instead of adding a CentOS repo to RHEL, enable the needed RHEL repos with rhsm_repository

For RHEL 7, we need the "extras" repo for container-selinux
For RHEL 8, we need the "appstream" repo for container-selinux, ipvsadm and socat

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

roles/container-engine/containerd/tasks/containerd_repo.yml

@@ -30,24 +30,3 @@
     src: "rh_containerd.repo.j2"
     dest: "{{ yum_repo_dir }}/containerd.repo"
   when: ansible_distribution in ["CentOS","RedHat"]
-
-- name: check if container-selinux is available
-  yum:
-    list: "container-selinux"
-  register: yum_result
-  when: ansible_distribution in ["CentOS","RedHat"]
-
-- name: Configure extras repository on RedHat/CentOS if container-selinux is not available in current repos
-  yum_repository:
-    name: extras
-    description: "CentOS-{{ ansible_distribution_major_version }} - Extras"
-    state: present
-    baseurl: "{{ extras_rh_repo_base_url }}"
-    file: "extras"
-    gpgcheck: "{{ 'yes' if extras_rh_repo_gpgkey else 'no' }}"
-    gpgkey: "{{ extras_rh_repo_gpgkey }}"
-    keepcache: "{{ containerd_rpm_keepcache | default('1') }}"
-    proxy: " {{ http_proxy | default('_none_') }}"
-  when:
-    - ansible_distribution in ["CentOS","RedHat"]
-    - yum_result.results | length == 0