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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",
...
```

dist_file_dict = {}
        dist_file_content = dist_file_content.strip(DistributionFiles.STRIP_QUOTES)
        if name in self.SEARCH_STRING:
            
            
            if self.SEARCH_STRING[name] in dist_file_content:
                
                dist_file_dict['distribution'] = name
                dist_file_dict['distribution_file_search_string'] = self.SEARCH_STRING[name]
            else:
                
                dist_file_dict['distribution'] = dist_file_content.split()[0]
            return True, dist_file_dict
        if name in self.OS_RELEASE_ALIAS:
            if self.OS_RELEASE_ALIAS[name] in dist_file_content:
                dist_file_dict['distribution'] = name
                return True, dist_file_dict
            return False, dist_file_dict
        
        
        try:
            
            distfunc_name = 'parse_distribution_file_' + name
            distfunc = getattr(self, distfunc_name)
            parsed, dist_file_dict = distfunc(name, dist_file_content, path, collected_facts)