Unable to sync security groups with source groups

Given this security group definition in the rubber.yml file:
```
security_groups:
  default:
    rules:
      - protocol: tcp
        from_port: 1
        to_port: 65535
        source_group_name: default
        source_group_account: "#{cloud_providers.aws.account}"
```

Fog won't return the group name within the groups hash, so it won't get set. For Rubber, this looks like a different rule within that security group. Here's the rubber output when trying to sync:

```
  * Security Group already in cloud, syncing rules: default
Rule '{"protocol"=>"udp", "from_port"=>"1", "to_port"=>"65535", "source_group_name"=>"", "source_group_account"=>"123456789"}' exists in cloud, but not locally, remove from cloud? [y/N]:
```

Probably the "groupId" should be used to retrieve the name of the group from Fog's original response.