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##### SUMMARY
<!--- Explain the problem briefly below -->
The ansible_distribution_version fact is displayed as "8" on Debian 9, when Plesk 18 is installed, because the /etc/plesk-release file is parsed.
It seems the setup module (_distro.py?) is parsing all /etc/*-release files on a target host, and this can mess with the ansible_distribution_version facts.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
setup

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
ansible 2.8.6
  config file = /etc/ansible/ansible.cfg
  configured module search path = ['/root/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/local/lib/python3.5/dist-packages/ansible
  executable location = /usr/local/bin/ansible
  python version = 3.5.3 (default, Sep 27 2018, 17:25:39) [GCC 6.3.0 20170516]
```

##### OS / ENVIRONMENT
<!--- Provide all relevant information below, e.g. target OS versions, network device firmware, etc. -->
```
root@web003:~# cat /etc/os-release
PRETTY_NAME="Debian GNU/Linux 9 (stretch)"
NAME="Debian GNU/Linux"
VERSION_ID="9"
VERSION="9 (stretch)"
VERSION_CODENAME=stretch
ID=debian
HOME_URL="https://www.debian.org/"
SUPPORT_URL="https://www.debian.org/support"
BUG_REPORT_URL="https://bugs.debian.org/"

root@web003:~# lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description:    Debian GNU/Linux 9.11 (stretch)
Release:        9.11
Codename:       stretch
```

##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->
Install Debian with Plesk 18, and run ansible setup against it.
If you can't install Plesk, just create the file /etc/plesk-release with this content:

```
18.0.19.3
Plesk Obsidian 18.0
```

<!--- Paste example playbooks or commands between quotes below -->
```yaml
ansible web003 -m setup -a "filter=ansible_dist*"
```

<!--- HINT: You can paste gist.github.com links for larger files -->

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->
`ansible_distribution_version` reports 9

```
    "ansible_facts": {
        "ansible_distribution": "Debian",
        "ansible_distribution_file_parsed": true,
        "ansible_distribution_file_path": "/etc/os-release",
        "ansible_distribution_file_variety": "Debian",
        "ansible_distribution_major_version": "9",
        "ansible_distribution_release": "stretch",
        "ansible_distribution_version": "9.11",
        "discovered_interpreter_python": "/usr/bin/python"
```

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->
<!--- Paste verbatim command output between quotes -->
`ansible_distribution_version` reports 8

```paste below
    "ansible_facts": {
        "ansible_distribution": "Debian",
        "ansible_distribution_file_parsed": true,
        "ansible_distribution_file_path": "/etc/os-release",
        "ansible_distribution_file_variety": "Debian",
        "ansible_distribution_major_version": "8",
        "ansible_distribution_release": "stretch",
        "ansible_distribution_version": "8.0.19.3",
        "discovered_interpreter_python": "/usr/bin/python"
```

"""Return the distro ID of the OS distribution, as a string.
        For details, see :func:`distro.id`.
        """
        def normalize(distro_id, table):
            distro_id = distro_id.lower().replace(' ', '_')
            return table.get(distro_id, distro_id)
        distro_id = self.os_release_attr('id')
        if distro_id:
            return normalize(distro_id, NORMALIZED_OS_ID)
        distro_id = self.lsb_release_attr('distributor_id')
        if distro_id:
            return normalize(distro_id, NORMALIZED_LSB_ID)
        distro_id = self.distro_release_attr('id')
        if distro_id:
            return normalize(distro_id, NORMALIZED_DISTRO_ID)
        distro_id = self.uname_attr('id')
        if distro_id:
            return normalize(distro_id, NORMALIZED_DISTRO_ID)
        return ''
    def name(self, pretty=False):