xci: Move VM provisioning to xci-deploy.sh

xci: Move VM provisioning to xci-deploy.sh

The bifrost-provision.sh script will provision machines using Ansible
playbooks. If we run this script in an Ansible playbook, that means that
we will run Ansible with Ansible and this can only lead to further
confusion when debugging issues. As such, since we already have a script
to provision machines, lets use it directly from the xci-deploy.sh
script. This also reverts 3f04e1fd72b14420788af64b14c35a5f74727f82 which
added virtualenv support in bifrost since that causes more problems than
it fixes for the time being.

Change-Id: Id82b7c06a2af28b66f64f1966227888227ec276f
Signed-off-by: Markos Chandras <mchandras@suse.de>