Make sure we pick flavors with disk
Make sure we pick flavors with disk

Modern nova disallows booting vms on flavors with disk: 0 unless
they are volume backed.

Change-Id: I527a607ba71d027daa9ac2553275f849fce1244a

openstack/python-openstacksdk,dtroyer/python-openstacksdk,stackforge/python-openstacksdk,openstack/python-openstacksdk,dtroyer/python-openstacksdk,stackforge/python-openstacksdk