Provision Safe Deploy

Right now, provision-deploy fails in spectacular fashion if you are putting the site on a platform with the same projects, but a different directory structure. Ignoring the mind-boggling issue that Drupal core doesn't treat the system registry as the cache that it is and simply refresh it if a path isn't valid, we can use the registry_rebuild project right before provision-deploy causes a bootstrap. Right now this is done on the pre_updatedb event, but obviously that doesn't work if the provision project starts calling some other set of commands that also require a bootstrap.