setup: added runOnce logic for VM os install

This is a first step, in future we'll try to
configure the devices boot order.
We ask the user to install the OS then press enter.
Then we shutdown the VM, destory it, reconfigure
for booting from disk, and create it again.

Change-Id: I9bfc182f575b0a1e864c18dbe251d912f51f272e
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>