fix(systemd units): Fix docker containers being orphaned

Docker seems to orphan our containers after the fix in 6b452e,
this reverts part of it and properly signals the docker containers to
stop. Given that we run them with `--rm`, this also makes the ephemeral
containers destroy their data off of the drives. The data containers are
not affected by this and they persist.

Author: Xe

systemd/deis-controller.service

@@ -9,6 +9,7 @@ TimeoutStartSec=20m
 ExecStartPre=/bin/sh -c "IMAGE=`/run/deis/bin/get_image /deis/controller`; docker history $IMAGE >/dev/null || docker pull $IMAGE"
 ExecStartPre=/bin/sh -c "docker inspect deis-controller >/dev/null && docker rm -f deis-controller || true"
 ExecStart=/bin/sh -c "IMAGE=`/run/deis/bin/get_image /deis/controller` && docker run --name deis-controller --rm -p 8000:8000 -e PUBLISH=8000 -e HOST=$COREOS_PRIVATE_IPV4 --volumes-from=deis-logger $IMAGE"
+ExecStopPost=/usr/bin/docker stop deis-controller
 
 [Install]
 WantedBy=multi-user.target