Honor test=True with friendlier return message in file.mknod state

Before:

```
    State: - file
    Name:      /dev/holmb
    Function:  mknod
        Result:    None
        Comment:   
        Changes:   
                   ----------
                   new:
                       Character device /dev/holmb created.
```

After:

```
    State: - file
    Name:      /dev/holmb
    Function:  mknod
        Result:    None
        Comment:   Character device /dev/holmb is set to be created
        Changes:   
```