Fixes apt_repository always reporting file uri repos as changed

Adding a local file repo with apt_repository would always report that it had changed, even if it was there already, e.g:
```yml
apt_repository: repo='deb file:/opt/repo /'
```
always returned:
```
changed: [172.16.32.16] => {"changed": true, "item": "", "repo": "deb file:/opt/repo /", "state": "present"}
```