Clean config path of bind mount volume

Fix #9168

Remove config path of bind mount volume if no containers are using it.
Why was this moved down?  Are you sure we want to receive the error on line 171 about containers using this volume, even though it cannot be deleted?   I think as soon as we know it's a bind mount we should return.  

If you still need to remove the `volume.configPath`  then you need to make that error about container usage conditional to this being a bind mount or not.  As simple:

```go
if volume.IsBindMount{
    return os.RemoveAll(volume.configPath)
}
```
should work fine.