Docker-link the backend service names use the public ip in name

[BrianAdams]

Currently:

{
"options": {
"host": "",
"port": 8000,
"protocol": "tcp",
"method": "wrr",
"persistent": false
},
"health": 1,
"backends": [
"swarm-node-2-motd-8000-tcp"
]
}

Seems like multiple backends will have non-unique names on the same host. I would expect something more like "swarm-node-2-motd-32768-tcp" which uses the port Docker assigned in the name.