To avoid the cost of converting nodepool image from qcow2 to raw on
compute nodes, just upload raw images (not qcow2).
Change-Id: I325af734f843fc618a40ca992a0086ffb1c21cfd
Depends-On: https://review.openstack.org/585838
Signed-off-by: Paul Belanger <pabelanger@redhat.com>