Fix error when specifying daemon_json

Symptom:
```
TASK [angstwad.docker_ubuntu : Creates override directory (systemd) owner=root, path=/etc/systemd/system/docker.service.d, state={{ daemon_json is not none or docker_http_proxy_defined or docker_https_proxy_defined | ternary('directory', 'absent') }}, group=root, mode=493] ***
fatal: [dockerhost]: FAILED! => {"changed": false, "failed": true, "msg": "value of state must be one of: file,directory,link,hard,touch,absent, got: True"}
```

See also sample usage of `ternary` at http://docs.ansible.com/ansible/latest/playbooks_filters.html#id7

Author: lucafavatella

tasks/main.yml

@@ -140,7 +140,7 @@
 - name: Creates override directory (systemd)
   file:
     path: /etc/systemd/system/docker.service.d
-    state: "{{ daemon_json is not none or docker_http_proxy_defined or docker_https_proxy_defined | ternary('directory', 'absent') }}"
+    state: "{{ (daemon_json is not none or docker_http_proxy_defined or docker_https_proxy_defined) | ternary('directory', 'absent') }}"
     owner: root
     group: root
     mode: 0755