Pin vagrant version on cinst command

Vagrant ~1.5 is having a gem fight with vagrant-berkshelf. While OpsCode and HashiCorp solve the problem, I propose we pin the version of Vagrant.

Also passing additional args to vagrant ssh via -- as suggested here: (https://groups.google.com/forum/#!topic/vagrant-up/yZC4--9Ygls) solved a problem I was having with setting init 5 automatically.

I am also having an issue where --auto-reboot on the vagrant vbguest command doesn't execute because the guest package apparently fails:
An error occurred during installation of VirtualBox Guest Additions 4.3.8. Some functionality may not work as intended.
In most cases it is OK that the "Window System drivers" installation failed.