image: add support for --debug arg
image: add support for --debug arg

Add a --debug arg which disables catching of exceptions when
running virt-sandbox-image, to make it easier to diagnose
unexpected crashes

Signed-off-by: Daniel P. Berrange <bb938cf255e055ff3507f2627d214e8e62118fcf@redhat.com>

agx/libvirt-sandbox-debian,agx/libvirt-sandbox-debian,libvirt/libvirt-sandbox,libvirt/libvirt-sandbox,libvirt/libvirt-sandbox,agx/libvirt-sandbox-debian,agx/libvirt-sandbox-debian,agx/libvirt-sandbox-debian