improve consistency
starting Couchbase via "start" instead of "restart"

* Couchbase is not yet running when the container starts
* therefore this output was always visible:
  NOTE: shutdown failed
  {badrpc,nodedown}
* using "start" prevents this error message
couchbase-cli does not require a running couchbase in its docker container
Merge branch 'darxriggs-couchbase' into couchbase