Handle architecture incompatibility errors better.

Example:

```
Successfully pulled pygmystack/ssh-agent
Failed to create amazeeio-ssh-agent: Error response from daemon: image with reference pygmystack/ssh-agent was found but does not match the specified platform: wanted linux/386, actual: linux/amd64
Failed to start amazeeio-ssh-agent: Error response from daemon: No such container: amazeeio-ssh-agent
```