Added updated fix to VT enable testing - EUCA-4231

With the current VT enable test, when the NC is started, the following is seen:

```
# service eucalyptus-nc start
Starting Eucalyptus services: vmx
done.
```

This fix makes sure the following behavior is seen:

```
# service eucalyptus-nc start
Starting Eucalyptus services: done.
```