Merge pull request #962 from edx/han/Vagrantfile

Use vagrant-vbguest plugin to sync VirtualBox Guest Editions versions

vagrant/release/devstack/Vagrantfile

@@ -62,6 +62,10 @@ Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
     vb.customize ["modifyvm", :id, "--natdnshostresolver1", "on"]
   end
  
+  # Use vagrant-vbguest plugin to make sure Guest Additions are in sync
+  config.vbguest.auto_reboot = true
+  config.vbguest.auto_update = true
+
   # Assume that the base box has the edx_ansible role installed
   # We can then tell the Vagrant instance to update itself.
   config.vm.provision "shell", inline: $script