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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"
```

include_lsb=True,
                 os_release_file='',
                 distro_release_file='',
                 include_uname=True):
        """
        The initialization method of this class gathers information from the
        available data sources, and stores that in private instance attributes.
        Subsequent access to the information items uses these private instance
        attributes, so that the data sources are read only once.
        Parameters:
        * ``include_lsb`` (bool): Controls whether the
          `lsb_release command output`_ is included as a data source.
          If the lsb_release command is not available in the program execution
          path, the data source for the lsb_release command will be empty.
        * ``os_release_file`` (string): The path name of the
          `os-release file`_ that is to be used as a data source.
          An empty string (the default) will cause the default path name to
          be used (see `os-release file`_ for details).
          If the specified or defaulted os-release file does not exist, the
          data source for the os-release file will be empty.
        * ``distro_release_file`` (string): The path name of the
          `distro release file`_ that is to be used as a data source.
          An empty string (the default) will cause a default search algorithm
          to be used (see `distro release file`_ for details).
          If the specified distro release file does not exist, or if no default
          distro release file can be found, the data source for the distro
          release file will be empty.
        * ``include_name`` (bool): Controls whether uname command output is