Add override to ensure ZFS starts before docker

Stolen with love from 7dda0bc7cb

ansible/roles/docker_cleanup/tasks/zfs-override.yml

@@ -0,0 +1,15 @@
+- name: Create dir for docker service ZFS override
+  file:
+    path: /etc/systemd/system/docker.service.d
+    state: directory
+    mode: "0755"
+  become: true
+
+- name: Create override.conf
+  copy:
+    src: files/zfs-override.conf
+    dest: /etc/systemd/system/docker.service.d/zfs-override.conf
+    owner: root
+    group: root
+    mode: "0644"
+  become: true