##### SUMMARY
win_domain_user always returns changed if a password is specified.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
win_domain_user

##### ANSIBLE VERSION
```paste below
ansible 2.8.1
  config file = /etc/ansible/ansible.cfg
  configured module search path = ['/home/user/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python3.7/site-packages/ansible
  executable location = /usr/bin/ansible
  python version = 3.7.3 (default, Mar 26 2019, 21:43:19) [GCC 8.2.1 20181127]
```

##### CONFIGURATION

##### OS / ENVIRONMENT

ArchLinux

##### STEPS TO REPRODUCE
```yaml
- name: Set AD User Password
      win_domain_user:
        name: '{{ user_name }}'
        password: '{{ password }}'
        state: present
- name: Set AD User Password again
      win_domain_user:
        name: '{{ user_name }}'
        password: '{{ password }}'
        state: present
```

##### EXPECTED RESULTS
The 2nd task to show as not changed.

##### ACTUAL RESULTS
The 2nd task shows as changed, even though the password was already set.
postal_code: 12345
    country: US
    attributes:
      telephoneNumber: 555-123456
- name: Ensure user bob is created and use custom credentials to create the user
  win_domain_user:
    name: bob
    firstname: Bob
    surname: Smith
    password: B0bP4ssw0rd
    state: present
    domain_username: DOMAIN\admin-account
    domain_password: SomePas2w0rd
    domain_server: domain@DOMAIN.COM
- name: Ensure user bob is present in OU ou=test,dc=domain,dc=local
  win_domain_user:
    name: bob
    password: B0bP4ssw0rd
    state: present
    path: ou=test,dc=domain,dc=local
    groups:
      - Domain Admins
- name: Ensure user bob is absent
  win_domain_user:
    name: bob
    state: absent
'''
RETURN = r'''
account_locked:
    description: true if the account is locked