Generating a warden manifest fails

```
concourse git:(master) ./generate_deployment_manifest warden
2014/08/13 15:48:50 error generating manifest: unresolved nodes:
    (( merge )) in ./templates/jobs.yml jobs.[2].properties.atc.config
    (( merge )) in ./templates/jobs.yml jobs.[2].properties.atc.basic_auth_username
    (( merge )) in ./templates/jobs.yml jobs.[2].properties.atc.basic_auth_encrypted_password
```
