Allow to not manage Tempest code in Puppet

In the case you are using a package, you may want the flexibility to not
use VCS to manage Tempest code and just use the Puppet module to
configure Tempest itself.

Adding a new parameter, true by default to keep backward compatibility.

(cherry picked from commit 05fc037265964e16429639e26601d8fd6d28ec4c)

Change-Id: I5b954b2b3d1b300dc8f75dd2147fe0c811c1c2ab