##### SUMMARY

The merge of #45507 broke `update_password="on_create"` on Alpine Linux with the shadow package installed.

This does not work anymore
```yml
  - name: add users                                                                                                                                                                                                                                  
    user:
      name: "{{ item.name }}"
      comment: "{ item.comment }}"
      shell: "/bin/zsh"
      password: '*'
      update_password: on_create
   with_items:
    ....
```

After the PR, all users that have a password that is not '*' will get their password changed.

Reverting bf3e397ea7922e8bd8b8ffbc05d1aede0317d119, makes 'update_password: on_create' work as expected again.

##### ISSUE TYPE
- Bug Report

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

lib/ansible/modules/system/user.py

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
2.8.7
```

##### CONFIGURATION
<!--- Paste verbatim output from "ansible-config dump --only-changed" between quotes -->
```paste below

```

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

Alpine Linux

##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->

<!--- Paste example playbooks or commands between quotes below -->
```yaml
  - name: add users                                                                                                                                                                                                                                  
    user:
      name: "{{ item.name }}"
      comment: "{ item.comment }}"
      shell: "/bin/zsh"
      password: '*'
      update_password: on_create
```

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

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

Users that are not created does not get their password changed.

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->

<!--- Paste verbatim command output between quotes -->
```paste below
Password "hash" changed to '*'
```

self.skeleton = module.params['skeleton']
        self.system = module.params['system']
        self.login_class = module.params['login_class']
        self.append = module.params['append']
        self.sshkeygen = module.params['generate_ssh_key']
        self.ssh_bits = module.params['ssh_key_bits']
        self.ssh_type = module.params['ssh_key_type']
        self.ssh_comment = module.params['ssh_key_comment']
        self.ssh_passphrase = module.params['ssh_key_passphrase']
        self.update_password = module.params['update_password']
        self.home = module.params['home']
        self.expires = None
        self.password_lock = module.params['password_lock']
        self.groups = None
        self.local = module.params['local']
        self.profile = module.params['profile']
        self.authorization = module.params['authorization']
        self.role = module.params['role']
        if module.params['groups'] is not None:
            self.groups = ','.join(module.params['groups'])
        if module.params['expires'] is not None:
            try:
                self.expires = time.gmtime(module.params['expires'])
            except Exception as e:
                module.fail_json(msg="Invalid value for 'expires' %s: %s" % (self.expires, to_native(e)))
        if module.params['ssh_key_file'] is not None:
            self.ssh_file = module.params['ssh_key_file']
        else:
            self.ssh_file = os.path.join('.ssh', 'id_%s' % self.ssh_type)
    def check_password_encrypted(self):