The Vagrant-Cloud and Vagrant provider (e.g. virtualbox, vmware_desktop
etc.) must be determined differently depending on the builder or
post-processor supplying the artifact.
Adds a wrapper function that:
* Uses the original method of determining the provider when the artifact
is provided by either the Vagrant builder or Vagrant post-processor
* Uses a new (currently empty) function when the artifact is provided
via the Artifice post-processor
e8c586175e