Fix ansible_distribution facts for Ubuntu 8.4 hardy

This patch fix ``ansible_distribution*`` facts running on Ubuntu 8.4 hardy

##### ansible all -m setup -a 'filter=ansible_distribution*' (before) : 
```
hardy64.dev | success >> {
    "ansible_facts": {
        "ansible_distribution": "Debian",
        "ansible_distribution_major_version": "lenny/sid",
        "ansible_distribution_release": "NA",
        "ansible_distribution_version": "lenny/sid"
    },
    "changed": false
}
```

##### ansible all -m setup -a 'filter=ansible_distribution*' (after) : 
```
hardy64.dev | success >> {
    "ansible_facts": {
        "ansible_distribution": "Debian",
        "ansible_distribution_major_version": "8",
        "ansible_distribution_release": "hardy",
        "ansible_distribution_version": "8.04"
    },
    "changed": false
}
```