Revert "Fixes #97, Triggers #98, Makes me sad: Fix Docker 18.09.0 startup issue on systemd systems."

This reverts commit d8a4438b3c.

tasks/docker-1809-shim.yml

@@ -1,10 +0,0 @@
----
-- name: Ensure containerd service dir exists.
-  file:
-    path: /etc/systemd/system/containerd.service.d
-    state: directory
-
-- name: Add shim to ensure Docker can start in all environments.
-  template:
-    src: override.conf.j2
-    dest: /etc/systemd/system/containerd.service.d/override.conf

tasks/main.yml

@@ -11,10 +11,6 @@
     state: "{{ docker_package_state }}"
   notify: restart docker
 
-# TODO: Remove this shim once 18.09.1 or later is released.
-- import_tasks: docker-1809-shim.yml
-  when: ansible_service_mgr == 'systemd'
-
 - name: Ensure Docker is started and enabled at boot.
   service:
     name: docker

templates/override.conf.j2

@@ -1,2 +0,0 @@
-[Service]
-ExecStartPre=