Revert "Use K8s 1.14 and add kubeadm experimental control plane mode (#4317)" (#4510)

This reverts commit 316508626d.

roles/kubernetes/master/tasks/kubeadm-secondary-experimental.yml

@@ -1,45 +0,0 @@
----
-- name: Set kubeadm_discovery_address
-  set_fact:
-    kubeadm_discovery_address: >-
-      {%- if "127.0.0.1" in kube_apiserver_endpoint or "localhost" in kube_apiserver_endpoint -%}
-      {{ first_kube_master }}:{{ kube_apiserver_port }}
-      {%- else -%}
-      {{ kube_apiserver_endpoint }}
-      {%- endif %}
-  tags:
-    - facts
-
-- name: Create kubeadm ControlPlane config
-  template:
-    src: "kubeadm-controlplane.{{ kubeadmConfig_api_version }}.yaml.j2"
-    dest: "{{ kube_config_dir }}/kubeadm-controlplane.yaml"
-    backup: yes
-  when:
-    - inventory_hostname != groups['kube-master']|first
-    - not kubeadm_already_run.stat.exists
-
-- name: Wait for k8s apiserver
-  wait_for:
-    host: "{{kubeadm_discovery_address.split(':')[0]}}"
-    port: "{{kubeadm_discovery_address.split(':')[1]}}"
-    timeout: 180
-
-- name: Joining control plane node to the cluster.
-  command: >-
-    {{ bin_dir }}/kubeadm join
-    --config {{ kube_config_dir}}/kubeadm-controlplane.yaml
-    --ignore-preflight-errors=all
-    {% if kubeadm_certificate_key is defined %}
-    --certificate-key={{ kubeadm_certificate_key }}
-    {% endif %}
-  register: kubeadm_join_control_plane
-  when:
-    - inventory_hostname != groups['kube-master']|first
-    - not kubeadm_already_run.stat.exists
-  environment:
-    PATH: "{{ bin_dir }}:{{ ansible_env.PATH }}"
-
-- name: Set secret_changed to false to avoid extra token rotation
-  set_fact:
-    secret_changed: false