Comment 1 for bug 1827392

Additionally, in this same vein it would be very useful to be able to specify arguments with ":" in them, i.e. to specify the address to connect to for another app in the same snap, we need to do this:

```
command: bin/device-random -confdir $SNAP_DATA/config/device-random -profile res --registry $CONSUL_ADDR
    environment:
      CONSUL_ADDR: "consul://localhost:8500"
```

Where ideally we would just be able to do:

```
command: bin/device-random -confdir $SNAP_DATA/config/device-random -profile res --registry=consul://localhost:8500
```