##### 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 '*'
```

cmd = self._get_dscl()
        cmd += ['-create', '/Users/%s' % self.name]
        (rc, err, out) = self.execute_command(cmd)
        if rc != 0:
            self.module.fail_json(msg='Cannot create user "%s".' % self.name, err=err, out=out, rc=rc)
        self._make_group_numerical()
        if self.uid is None:
            self.uid = str(self._get_next_uid(self.system))
        
        if self.create_home:
            if self.home is None:
                self.home = '/Users/%s' % self.name
            if not self.module.check_mode:
                if not os.path.exists(self.home):
                    os.makedirs(self.home)
                self.chown_homedir(int(self.uid), int(self.group), self.home)
        
        
        if not self.system and self.shell is None:
            self.shell = '/bin/bash'
        for field in self.fields:
            if field[0] in self.__dict__ and self.__dict__[field[0]]:
                cmd = self._get_dscl()
                cmd += ['-create', '/Users/%s' % self.name, field[1], self.__dict__[field[0]]]
                (rc, _err, _out) = self.execute_command(cmd)
                if rc != 0:
                    self.module.fail_json(msg='Cannot add property "%s" to user "%s".' % (field[0], self.name), err=err, out=out, rc=rc)
                out += _out
                err += _err
                if rc != 0: