chore(controller): remove $PORT logic from fleet

For buildpack apps, [$PORT is exposed][1] as part of slugrunner's job.
For Dockerfile/Docker images, the internal port numbers are already
known to the developer, so if they want to follow 12-factor best
practices then they will have set up $PORT in their own image.

deis/publisher exposes the port with the lowest numerical value to the
router, which is why the documentation is reflected to show this.

https://github.com/deis/deis/blob/e6a078b4119887b4de73e8a6d04291b7cdeb823b/builder/image/slugrunner/Dockerfile#L10-L12

Author: Matthew Fisher

scheduler/fleet.py

@@ -379,7 +379,7 @@ def attach(self, name):
     {"section": "Unit", "name": "Description", "value": "{name}"},
     {"section": "Service", "name": "ExecStartPre", "value": '''/bin/sh -c "IMAGE=$(etcdctl get /deis/registry/host 2>&1):$(etcdctl get /deis/registry/port 2>&1)/{image}; docker pull $IMAGE"'''},  # noqa
     {"section": "Service", "name": "ExecStartPre", "value": '''/bin/sh -c "docker inspect {name} >/dev/null 2>&1 && docker rm -f {name} || true"'''},  # noqa
-    {"section": "Service", "name": "ExecStart", "value": '''/bin/sh -c "IMAGE=$(etcdctl get /deis/registry/host 2>&1):$(etcdctl get /deis/registry/port 2>&1)/{image}; port=$(docker inspect -f '{{{{range $k, $v := .ContainerConfig.ExposedPorts }}}}{{{{$k}}}}{{{{end}}}}' $IMAGE | cut -d/ -f1) ; docker run --name {name} {memory} {cpu} {hostname} -P -e PORT=$port $IMAGE {command}"'''},  # noqa
+    {"section": "Service", "name": "ExecStart", "value": '''/bin/sh -c "IMAGE=$(etcdctl get /deis/registry/host 2>&1):$(etcdctl get /deis/registry/port 2>&1)/{image}; docker run --name {name} {memory} {cpu} {hostname} -P $IMAGE {command}"'''},  # noqa
     {"section": "Service", "name": "ExecStop", "value": '''/usr/bin/docker stop {name}'''},
     {"section": "Service", "name": "ExecStop", "value": '''/usr/bin/docker rm -f {name}'''},
     {"section": "Service", "name": "TimeoutStartSec", "value": "20m"},