Include the vid of a new draft in the node object

The attached patch makes a small modification to the state_flow.module file to include the vid of the new draft revision in the node object so that other modules can have easy access to this information.

For example, we needed a way to redirect users back to the node edit form for the new draft revision after the save rather than following the default action of redirecting to the view page. This update allows us to easily pick up the correct vid rather than having to parse the $_GET['destination'] parameter or requerying the database.