Comment 5 for bug 1963907

So with above https://review.opendev.org/c/openstack/neutron-tempest-plugin/+/832640 fix, lot of neutron tempest plugin failure is gone.

Below are the current failing tests:
```
neutron_tempest_plugin.scenario.test_port_forwardings.PortForwardingTestJSON.test_port_forwarding_to_2_servers[id-ab40fc48-ca8d-41a0-b2a3-f6679c847bfe]
-------------------------------------------------------------------------------------------------------------------------------------------------------

Captured traceback:
~~~~~~~~~~~~~~~~~~~
    Traceback (most recent call last):

      File "/usr/lib/python3.9/site-packages/neutron_tempest_plugin/scenario/test_port_forwardings.py", line 126, in test_port_forwarding_to_2_servers
    servers = self._prepare_resources(num_servers=2,

      File "/usr/lib/python3.9/site-packages/neutron_tempest_plugin/scenario/test_port_forwardings.py", line 67, in _prepare_resources
    server = self.create_server(

      File "/usr/lib/python3.9/site-packages/neutron_tempest_plugin/scenario/base.py", line 147, in create_server
    self.wait_for_guest_os_ready(server['server'], client=client)

      File "/usr/lib/python3.9/site-packages/neutron_tempest_plugin/scenario/base.py", line 542, in wait_for_guest_os_ready
    utils.wait_until_true(system_booted, timeout=90, sleep=5)

      File "/usr/lib/python3.9/site-packages/neutron_tempest_plugin/common/utils.py", line 82, in wait_until_true
    while not predicate():

      File "/usr/lib/python3.9/site-packages/neutron_tempest_plugin/scenario/base.py", line 535, in system_booted
    console_output = client.get_console_output(server['id'])['output']

      File "/usr/lib/python3.9/site-packages/tempest/lib/services/compute/servers_client.py", line 649, in get_console_output
    return self.action(server_id, 'os-getConsoleOutput',

      File "/usr/lib/python3.9/site-packages/tempest/lib/services/compute/servers_client.py", line 221, in action
    resp, body = self.post('servers/%s/action' % server_id,

      File "/usr/lib/python3.9/site-packages/tempest/lib/common/rest_client.py", line 299, in post
    return self.request('POST', url, extra_headers, headers, body, chunked)

      File "/usr/lib/python3.9/site-packages/tempest/lib/services/compute/base_compute_client.py", line 47, in request
    resp, resp_body = super(BaseComputeClient, self).request(

      File "/usr/lib/python3.9/site-packages/tempest/lib/common/rest_client.py", line 703, in request
    self._error_checker(resp, resp_body)

      File "/usr/lib/python3.9/site-packages/tempest/lib/common/rest_client.py", line 879, in _error_checker
    raise exceptions.ServerFault(resp_body, resp=resp,

    tempest.lib.exceptions.ServerFault: Got server fault
Details: Unexpected API Error. Please report this at http://bugs.launchpad.net/nova/ and attach the Nova API log if possible.
<class 'oslo_db.exception.DBConnectionError'>

```

and

```
tempest.scenario.test_network_v6.TestGettingAddress.test_slaac_from_os[compute,id-2c92df61-29f0-4eaa-bee3-7c65bef62a43,network,slow]
------------------------------------------------------------------------------------------------------------------------------------

Captured traceback:
~~~~~~~~~~~~~~~~~~~
    Traceback (most recent call last):

      File "/usr/lib/python3.9/site-packages/tempest/common/utils/__init__.py", line 70, in wrapper
    return f(*func_args, **func_kwargs)

      File "/usr/lib/python3.9/site-packages/tempest/scenario/test_network_v6.py", line 244, in test_slaac_from_os
    self._prepare_and_test(address6_mode='slaac')

      File "/usr/lib/python3.9/site-packages/tempest/scenario/test_network_v6.py", line 193, in _prepare_and_test
    sshv4_1, ips_from_api_1, srv1 = self.prepare_server(networks=net_list)

      File "/usr/lib/python3.9/site-packages/tempest/scenario/test_network_v6.py", line 129, in prepare_server
    srv = self.create_server(

      File "/usr/lib/python3.9/site-packages/tempest/scenario/manager.py", line 309, in create_server
    body, _ = compute.create_test_server(

      File "/usr/lib/python3.9/site-packages/tempest/common/compute.py", line 294, in create_test_server
    LOG.exception('Server %s failed to delete in time',

      File "/usr/lib/python3.9/site-packages/oslo_utils/excutils.py", line 227, in __exit__
    self.force_reraise()

      File "/usr/lib/python3.9/site-packages/oslo_utils/excutils.py", line 200, in force_reraise
    raise self.value

      File "/usr/lib/python3.9/site-packages/tempest/common/compute.py", line 264, in create_test_server
    waiters.wait_for_server_status(

      File "/usr/lib/python3.9/site-packages/tempest/common/waiters.py", line 66, in wait_for_server_status
    body = client.show_server(server_id)['server']

      File "/usr/lib/python3.9/site-packages/tempest/lib/services/compute/servers_client.py", line 153, in show_server
    resp, body = self.get("servers/%s" % server_id)

      File "/usr/lib/python3.9/site-packages/tempest/lib/common/rest_client.py", line 314, in get
    return self.request('GET', url, extra_headers, headers)

      File "/usr/lib/python3.9/site-packages/tempest/lib/services/compute/base_compute_client.py", line 47, in request
    resp, resp_body = super(BaseComputeClient, self).request(

      File "/usr/lib/python3.9/site-packages/tempest/lib/common/rest_client.py", line 703, in request
    self._error_checker(resp, resp_body)

      File "/usr/lib/python3.9/site-packages/tempest/lib/common/rest_client.py", line 879, in _error_checker
    raise exceptions.ServerFault(resp_body, resp=resp,

    tempest.lib.exceptions.ServerFault: Got server fault
Details: Unexpected API Error. Please report this at http://bugs.launchpad.net/nova/ and attach the Nova API log if possible.
<class 'oslo_db.exception.DBConnectionError'>
```

It seems to be specifically related to Nova.