tempest.api.compute.servers.test_device_tagging fails with libvirt-xen

On the Xen Project CI, two new tests always fails:

tempest.api.compute.servers.test_device_tagging.DeviceTaggingTest.test_device_tagging
tempest.api.compute.servers.test_device_tagging.DeviceTaggingTestV2_42.test_device_tagging

It appear that the test is trying to ssh to the instance while the instance itself is powering off.

from tempest, Captured pythonlogging:
    2017-05-31 07:41:22,451 28296 INFO [tempest.api.compute.servers.test_device_tagging] Attempting to verify tagged devices in server d7004fb9-c241-4976-befb-85af3771778f via the metadata service: http://169.254.169.254/openstack/latest/meta_data.json
    2017-05-31 07:41:22,452 28296 DEBUG [tempest.lib.common.utils.linux.remote_client] Remote command: set -eu -o pipefail; PATH=$PATH:/sbin; curl -V
    2017-05-31 07:41:22,453 28296 INFO [tempest.lib.common.ssh] Creating ssh connection to '172.24.5.4:22' as 'cirros' with public key authentication
    2017-05-31 07:41:25,451 28296 WARNING [tempest.lib.common.ssh] Failed to establish authenticated ssh connection to cirros@172.24.5.4 ([Errno None] Unable to connect to port 22 on 172.24.5.4). Number attempts: 1. Retry after 2 seconds.

From screen-n-cpu.txt.gz:
May 31 07:41:30.385202 ds-xen-rax-iad-10748 nova-compute[21012]: DEBUG nova.virt.driver [-] Emitting event <LifecycleEvent: 1496216475.24, d7004fb9-c241-4976-befb-85af3771778f => Stopped> {{(pid=21012) emit_event /opt/stack/new/nova/nova/virt/driver.py:1446}}
May 31 07:41:30.385567 ds-xen-rax-iad-10748 nova-compute[21012]: INFO nova.compute.manager [-] [instance: d7004fb9-c241-4976-befb-85af3771778f] VM Stopped (Lifecycle Event)

More logs can be found at:
http://logs.openstack.xenproject.org/80/394480/35/check/dsvm-tempest-xen/ef343be/