redis:start fails to start ambassador

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Description of problem

When a Redis instance that has expose is stopped (redis:stop) the ambassador is correctly stopped but a dokku redis:start will not start ambassador giving error

How reproducible

Steps to Reproduce

1. dokku redis:create redis-test
2. dokku redis:expose redis-test
3. dokku redis:stop redis-test
4. dokku redis:start redis-test

Actual Results

=====> Starting container
Error response from daemon: Cannot link to a non running container: /dokku.redis.redis-test AS /dokku.redis.redis-test.ambassador/redis
Error: failed to start containers: dokku.redis.redis-test.ambassador

Expected Results

=====> Starting container
=====> Container started