Issue title: Host DNS is cleared by container
 Issue body: I use Ansible to provision and maintain my docker configuration. After some system maintenance / version bumping the container, I now lose DNS on my _host_ when the docker container comes up. Forcing a DHCP renew on my host refreshes DNS temporarily:

```
> cat /etc/resolv.conf
# Generated by dhclient or interface enp0s31f6
domain home
search home
nameserver 116.69.203.115

> ping -c 1 example.com
PING example.com (116.69.203.115) 56(84) bytes of data.
64 bytes from 116.69.203.115 (116.69.203.115): icmp_seq=1 ttl=54 time=167 ms

--- example.com ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 167.005/167.005/167.005/0.000 ms

> docker start downloader
downloader

> cat /etc/resolv.conf
# Generated by dhcpcd
# /etc/resolv.conf.head can replace this line
# /etc/resolv.conf.tail can replace this line

> ping -c 1 example.com
ping: example.com: Temporary failure in name resolution

> dhclient enp0s31f6
RTNETLINK answers: File exists

> cat /etc/resolv.conf
# Generated by dhclient or interface enp0s31f6
domain home
search home
nameserver 116.69.203.115

> ping -c 1 example.com
ping: example.com: Temporary failure in name resolution

> cat /etc/resolv.conf
# Generated by dhcpcd
# /etc/resolv.conf.head can replace this line
# /etc/resolv.conf.tail can replace this line
```

Container config is as follows:
```
- name: "Configure docker/transmission"
  docker_container:
    name: downloader
    image: haugene/transmission-openvpn:2.3
    volumes:
      - "/mnt/8tb/downloads:/data"
      - "/etc/localtime:/etc/localtime:ro"
    capabilities:
      - NET_ADMIN
    published_ports:
      - "9091:9091"
    env:
       PUID: 666
       PGID: 666
       OPENVPN_*: <<snip>>
       TRANSMISSION_*: <<snip>>
       LOCAL_NETWORK: "116.69.203.115/16"
    dns_servers:
      - "116.69.203.115"
      - "116.69.203.115"
    log_driver: json-file
    log_options:
      max-size: 10m
    devices:
      /dev/net/tun
    restart_policy: "unless-stopped"
```

Any help is appreciated :) 
 Comments: 
 Comment 0: For whatever reason, dhcpcd was clearing my hosts resolv.conf on start/stop/restart of the docker container. I'm unsure how docker / the container / dhcpcd interact, but removing dhcpcd in favor of dhclient resolved the issue for me.
{'source': 'GithubIssues', 'repo_name_with_owner': 'haugene/docker-transmission-openvpn', 'issue_id': 365278698, 'repo_stars': 3267.0}