adding the usage of virtual_domains along with other file types other th...

adding the usage of virtual_domains along with other file types other than hash
Why have all these 'type' lines in the case statement? Would make more sense to put them in between these lines starting at line 23 right?

```
default['postfix']['aliases'] = {}
default['postfix']['transports'] = {}
default['postfix']['access'] = {}
default['postfix']['virtual_aliases'] = {}
```

It that case you only have to add these lines once...