Use the same volume size in all VM creation attempts
Use the same volume size in all VM creation attempts

If the first attempt at VM creation fails, we try again, but for
some reason we use a 100 GB volume size instead of 80 GB for the
first try.

Let's be consistent, otherwise we can cause quota errors.

Change-Id: I994583e0e0ef6ec7085b800ab9f7b33c53035045

rdo-infra/ci-config,rdo-infra/ci-config,redhat-openstack/rdo-infra,rdo-infra/ci-config,redhat-openstack/rdo-infra,rdo-infra/ci-config,redhat-openstack/rdo-infra,redhat-openstack/rdo-infra