Windows shutdown command errors - NT_STATUS_OBJECT_NAME_NOT_FOUND
### Backstory
I set up WOL for my Windows PC on my RPi. The wake command works great, but the shutdown command is producing errors.

### Issue
The error NT_STATUS_OBJECT_NAME_NOT_FOUND is logged when the following shutdown command is sent:
`sudo net rpc shutdown --ipaddress 192.168.1.63 --user <username>%<password>`
I also tried without sudo, which produced the same error.

### Environment
* os & os version: Raspian9
* node version: v10.15.0
* homebridge version: v0.4.46
* homebridge-wol version: v3.2.4

### Configuration
My configuration looks like this:
```
"accessories": [
        {
            "accessory": "NetworkDevice",
            "name": "My PC",
            "mac": "<mac-address>",
            "ip": "192.168.1.63",
            "shutdownCommand": "sudo net rpc shutdown --ipaddress 192.168.1.63 --user <username>%<password>"
        }
    ],
```

### Log
```
[2/1/2019, 9:43:47 PM] [My PC] NetworkDevice "My PC" (192.168.1.63) went from status "Online" to "Shutting Down"
[2/1/2019, 9:43:48 PM] [My PC] An error occured while trying to shut down "My PC" (192.168.1.63): Error: Command failed: sudo net rpc shutdown --ipaddress 192.168.1.63 --user <username>%<password>
Could not initialise pipe winreg. Error was NT_STATUS_OBJECT_NAME_NOT_FOUND
```