##### 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 '*'
```

maybe_invalid = True
                    else:
                        maybe_invalid = True
            if maybe_invalid:
                self.module.warn("The input password appears not to have been hashed. "
                                 "The 'password' argument must be encrypted for this module to work properly.")
    def execute_command(self, cmd, use_unsafe_shell=False, data=None, obey_checkmode=True):
        if self.module.check_mode and obey_checkmode:
            self.module.debug('In check mode, would have run: "%s"' % cmd)
            return (0, '', '')
        else:
            
            cmd = [str(x) for x in cmd]
            return self.module.run_command(cmd, use_unsafe_shell=use_unsafe_shell, data=data)
    def backup_shadow(self):
        if not self.module.check_mode and self.SHADOWFILE:
            return self.module.backup_local(self.SHADOWFILE)
    def remove_user_userdel(self):
        if self.local:
            command_name = 'luserdel'
        else:
            command_name = 'userdel'
        cmd = [self.module.get_bin_path(command_name, True)]
        if self.force:
            cmd.append('-f')
        if self.remove:
            cmd.append('-r')
        cmd.append(self.name)
        return self.execute_command(cmd)
    def create_user_useradd(self):