Do not configure kvm virt_type in devstack
Do not configure kvm virt_type in devstack

Disable the configuration of the kvm virt_type in devstack
as some of the nodes in infra are exhibiting a bug [1] and
failing the gate.

[1] https://bugs.launchpad.net/ubuntu/+source/linux-lts-xenial/+bug/1682077

Change-Id: I4a59914cd14a9b88bad91adb09fd4235cb923907

zhangg/trove,openstack/trove,zhangg/trove,openstack/trove