### SUMMARY

Running the example playbook from https://docs.ansible.com/ansible/latest/modules/redfish_command_module.html#examples to disable and delete a certain user works as expected, but results in an error message

> The specified value is not allowed to be configured if the user name \\nor password is blank.'

Note that the user to be deleted (in the example below the user with id 5) _is different_ from the user specified in "username".  
The user (in the example below the user with id 5) is deleted as expected despite the error message.


##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
redfish_command

##### ANSIBLE VERSION
```
ansible 2.10.0.dev0
  config file = /home/ansible/ansible_local/ansible.cfg
  configured module search path = [u'/home/ansible/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python2.7/site-packages/ansible
  executable location = /usr/bin/ansible
  python version = 2.7.5 (default, Aug  7 2019, 00:51:29) [GCC 4.8.5 20150623 (Red Hat 4.8.5-39)]
```

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

```

##### OS / ENVIRONMENT
CentOS Linux release 7.6.1810 (Core)  
Dell R640, iDRAC Firmware 3.32.32.32


##### STEPS TO REPRODUCE
```yaml
- name: Disable and delete user
  hosts: dellR640
  gather_facts: False
  tasks:
    - name: Disable and delete user with id 5
      local_action:
        module: redfish_command
        category: Accounts
        command: ["DisableUser", "DeleteUser"]
        baseuri: "{{ baseuri }}"
        username: "{{ username }}"
        password: "{{ password }}"
        id: "5"
```


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


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

<!--- Paste verbatim command output between quotes -->
```
fatal: [dellR640 -> localhost]: FAILED! => {
    "changed": false, 
    "invocation": {
        "module_args": {
            "account_properties": {}, 
            "baseuri": "dellR640idrac", 
            "boot_next": null, 
            "bootdevice": null, 
            "category": "Accounts", 
            "command": [
                "DisableUser", 
                "DeleteUser"
            ], 
            "id": "5", 
            "new_password": null, 
            "new_username": null, 
            "password": "VALUE_SPECIFIED_IN_NO_LOG_PARAMETER", 
            "resource_id": null, 
            "roleid": null, 
            "timeout": 10, 
            "uefi_target": null, 
            "update_username": null, 
            "username": "customadminuser"
        }
    }, 
    "msg": "HTTP Error 400 on PATCH request to 'https://dellR640idrac/redfish/v1/Managers/iDRAC.Embedded.1/Accounts/5', extended message: 'The specified value is not allowed to be configured if the user name \\nor password is blank.'"
}
```

return response
        data = response['data']
        for service_name in payload.keys():
            if service_name not in data:
                return {'ret': False, 'msg': "%s service not supported" % service_name}
            for service_property in payload[service_name].keys():
                if service_property not in data[service_name]:
                    return {'ret': False, 'msg': "%s property for %s service not supported" % (service_property, service_name)}
        
        need_change = False
        for service_name in payload.keys():
            for service_property in payload[service_name].keys():
                value = payload[service_name][service_property]
                if value != data[service_name][service_property]:
                    need_change = True
                    break
        if not need_change:
            return {'ret': True, 'changed': False, 'msg': "Manager NetworkProtocol services already set"}
        response = self.patch_request(self.root_uri + networkprotocol_uri, payload)
        if response['ret'] is False:
            return response
        return {'ret': True, 'changed': True, 'msg': "Modified Manager NetworkProtocol services"}
    @staticmethod
    def to_singular(resource_name):
        if resource_name.endswith('ies'):
            resource_name = resource_name[:-3] + 'y'
        elif resource_name.endswith('s'):
            resource_name = resource_name[:-1]
        return resource_name
    def get_health_resource(self, subsystem, uri, health, expanded):