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##### SUMMARY
When i collect facts from TrueNAS, with the command : `ansible truenas -m setup | grep "ansible_distribution"`
the variable "ansible_distribution_major_version" is missing.
When i use same command on debian host, the variable is stell here

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
lib/ansible/module_utils/facts

##### ANSIBLE VERSION
```
ansible 2.10.2
  config file = /srv/ansible/ansible.cfg
  configured module search path = ['/srv/ansible/library']
  ansible python module location = /srv/ansible-venv/lib/python3.7/site-packages/ansible
  executable location = /srv/ansible-venv/bin/ansible
  python version = 3.7.3 (default, Dec 20 2019, 18:57:59) [GCC 8.3.0]
```

##### CONFIGURATION
<!--- Paste verbatim output from "" between quotes -->
```
ANSIBLE_FORCE_COLOR(/srv/ansible/ansible.cfg) = True
DEFAULT_HOST_LIST(/srv/ansible/ansible.cfg) = ['/srv/ansible/site.host']
DEFAULT_JINJA2_EXTENSIONS(/srv/ansible/ansible.cfg) = jinja2.ext.do
DEFAULT_MANAGED_STR(/srv/ansible/ansible.cfg) = Gestion par Ansible: {file} modifie le %Y-%m-%d %H:%M:%S par {uid} depuis {host}
DEFAULT_MODULE_PATH(/srv/ansible/ansible.cfg) = ['/srv/ansible/library']
DEFAULT_ROLES_PATH(/srv/ansible/ansible.cfg) = ['/srv/ansible/roles']
DEFAULT_STDOUT_CALLBACK(/srv/ansible/ansible.cfg) = yaml
DISPLAY_SKIPPED_HOSTS(/srv/ansible/ansible.cfg) = False
INTERPRETER_PYTHON(/srv/ansible/ansible.cfg) = auto_silent
RETRY_FILES_ENABLED(/srv/ansible/ansible.cfg) = False

```

##### OS / ENVIRONMENT
<!--- Provide all relevant information below, e.g. target OS versions, network device firmware, etc. -->


##### STEPS TO REPRODUCE
ansible truenas -m setup | grep "ansible_distribution"

##### EXPECTED RESULTS
```
...
        "ansible_distribution": "FreeBSD",
        "ansible_distribution_release": "12.2-RC3",
        "ansible_distribution_major_version": "12",
        "ansible_distribution_version": "FreeBSD 12.2-RC3 7c4ec6ff02c(HEAD) TRUENAS",
...
```


##### ACTUAL RESULTS
```
...
        "ansible_distribution": "FreeBSD",
        "ansible_distribution_release": "12.2-RC3",
        "ansible_distribution_version": "FreeBSD 12.2-RC3 7c4ec6ff02c(HEAD) TRUENAS",
...
```

sunos_facts['distribution'] = data.split()[0]
            sunos_facts['distribution_version'] = data.split()[1]
            sunos_facts['distribution_release'] = ora_prefix + data
            sunos_facts['distribution_major_version'] = uname_r.split('.')[1].rstrip()
            return sunos_facts
        uname_v = get_uname(self.module, flags=['-v'])
        distribution_version = None
        if 'SmartOS' in data:
            sunos_facts['distribution'] = 'SmartOS'
            if _file_exists('/etc/product'):
                product_data = dict([l.split(': ', 1) for l in get_file_content('/etc/product').splitlines() if ': ' in l])
                if 'Image' in product_data:
                    distribution_version = product_data.get('Image').split()[-1]
        elif 'OpenIndiana' in data:
            sunos_facts['distribution'] = 'OpenIndiana'
        elif 'OmniOS' in data:
            sunos_facts['distribution'] = 'OmniOS'
            distribution_version = data.split()[-1]
        elif uname_v is not None and 'NexentaOS_' in uname_v:
            sunos_facts['distribution'] = 'Nexenta'
            distribution_version = data.split()[-1].lstrip('v')
        if sunos_facts.get('distribution', '') in ('SmartOS', 'OpenIndiana', 'OmniOS', 'Nexenta'):
            sunos_facts['distribution_release'] = data.strip()
            if distribution_version is not None:
                sunos_facts['distribution_version'] = distribution_version
            elif uname_v is not None:
                sunos_facts['distribution_version'] = uname_v.splitlines()[0].strip()
            return sunos_facts
        return sunos_facts
class DistributionFactCollector(BaseFactCollector):