Revert "Revert "Run with KVM if we can in tests""

Instances are failing to launch on OVH in Tempest runs with the following:
KVM: entry failed, hardware error 0x0

Octavia team reporting the same.

This reverts commit a771ef5a03.

Change-Id: Ib495bddfe5a48ffd8e075eb9e27a8e0c9afb685f

common-tasks/test-set-nodepool-vars.yml

@@ -34,6 +34,9 @@
         echo "galera_percona_xtrabackup_repo_host=${NODEPOOL_PERCONA_PROXY}"
         echo "openstack_hosts_rdo_mirror_url=${NODEPOOL_RDO_PROXY}"
         echo "galera_repo_host=${NODEPOOL_MIRROR_HOST}:8080"
+        if [[ ${NODEPOOL_PYPI_MIRROR} == *.ovh.* ]]; then
+          echo "nova_virt_type=qemu"
+        fi
         echo "repo_build_pip_default_index=${NODEPOOL_PYPI_MIRROR}"
       args:
         executable: /bin/bash