Create one config for each release: lucid, precise and trusty

Just provide an easier way to test roles in all the releases..

```
$ vagrant up --no-provision # ups the 3 machines
Bringing machine 'precise' up with 'virtualbox' provider...
Bringing machine 'trusty' up with 'virtualbox' provider...
Bringing machine 'lucid' up with 'virtualbox' provider...
...
$ vagrant provision lucid
$ vagrant ... <release>
etc.
```