virsh: fail on any of the virt-customize commands
virsh: fail on any of the virt-customize commands

need to ensure we are failing ansible shell task
in case any of the virt-customize tasks fails
(they are responsible for preparing uc/oc base rhel-guest image)

also do not depend with customization steps on image existing or not,
instead depend on if the virt-customize steps already finished
on given image or not (use img-name.customized file existence for this)

Change-Id: I1d0f68e50aab52ddccf23e7f39e44a504e21e49e

okolisny/InfraRed,okolisny/InfraRed,redhat-openstack/infrared,redhat-openstack/infrared,redhat-openstack/infrared,okolisny/InfraRed