##### 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 '*'
```

groups_need_mod = True
            else:
                groups = self.get_groups_set(remove_existing=False)
                group_diff = set(current_groups).symmetric_difference(groups)
                if group_diff:
                    if self.append:
                        for g in groups:
                            if g in group_diff:
                                if has_append:
                                    cmd.append('-a')
                                groups_need_mod = True
                                break
                    else:
                        groups_need_mod = True
            if groups_need_mod and not self.local:
                if self.append and not has_append:
                    cmd.append('-A')
                    cmd.append(','.join(group_diff))
                else:
                    cmd.append('-G')
                    cmd.append(','.join(groups))
        if self.comment is not None and info[4] != self.comment:
            cmd.append('-c')
            cmd.append(self.comment)
        if self.home is not None and info[5] != self.home:
            cmd.append('-d')
            cmd.append(self.home)
            if self.move_home:
                cmd.append('-m')
        if self.shell is not None and info[6] != self.shell: