Handle no aws config

```
root@26fee6707066:/app/build# sawsh
there was an error listing instances in us-east-1 NoCredentialProviders: no valid providers in chain. Deprecated.
        For verbose messaging see aws.Config.CredentialsChainVerboseErrors
2018/04/04 18:05:26 NoCredentialProviders: no valid providers in chain. Deprecated.
        For verbose messaging see aws.Config.CredentialsChainVerboseErrors
```