Fix VMWare Fusion 6 compatability

Make vmx file generation compatible with the latest VMWare Fusion 6. 

We still have to specify boot order for Fusion 6*, otherwise some OS wouldn't load. Could be easily reproduced with windows-2008R2-serverstandard-amd64-winrm, without bootOrder the VM wouldn't start installation.
Merge pull request #944 from artemyarulin/Fusion6-compatibly-fix

Fix VMWare Fusion 6 compatability