The CoreOS ramdisk can take anywhere from 300-500 seconds to
startup depending on the size of the image and the underlying
hypervisor performance.
Given this time window, it is easy to cause the CI job to
timeout. Lets let the VM engine be chosen to use KVM if
available.
Change-Id: Ie4e096ccd71a3667fea34731cd5268b56e3cd2b9
5c94cc434c