rancher: Upgrading service should not result in loss of volume data

Rancher Version: rancher/server:v1.1.0-dev3 rancher/agent:v1.0.1 rancher/agent-instance:v0.8.1 rancher-compose-v0.8.2

Docker Version: 1.10.3

Steps to Reproduce:

Given the docker-compose.yml:

test:
  tty: true
  image: ubuntu:14.04.3
  stdin_open: true
  volumes:
  - /opt/mount

Run:

$ rancher-compose up

Exec into the created container and run:

$ touch /opt/mount/data.txt

Edit docker-compose.yml changing image to ubuntu:14.04.4

Run:

$ rancher-compose up --upgrade $ rancher-compose up --upgrade --confirm-upgrade

Exec into the created container and run:

$ cat /opt/mount/data.txt

Results: cat: /opt/mount/data.txt: No such file or directory

Expected: The data should not be lost.

The volume should be re-used for the replacement container. Specifically, the new container should be created using the existing container volume as named volume. For example: Given that the previous container had the volume named 9f411c6...87210 mounted in /opt/mount, then the new container should be created with the named volume 9f411c6...87210:/opt/mount. Additionally, the new container would need to be scheduled to the host that has the previous container.

Reference for how this works in in docker-compose: https://github.com/docker/compose/pull/2934 https://github.com/docker/libcompose/pull/89