Temptest test failures wallaby: test_create_update_port_with_dns_name

[Amol Kahat]

Description
===========

- Tempest test neutron_tempest_plugin.api.test_ports.PortsTestJSON.test_create_update_port_with_dns_name failed.

Actual Result
=============

Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/tempest/common/utils/__init__.py", line 89, in wrapper
    return func(*func_args, **func_kwargs)
  File "/usr/lib/python3.6/site-packages/neutron_tempest_plugin/api/test_ports.py", line 86, in test_create_update_port_with_dns_name
    self.assertEqual('d1', body['dns_name'])
  File "/usr/lib/python3.6/site-packages/testtools/testcase.py", line 411, in assertEqual
    self.assertThat(observed, matcher, message)
  File "/usr/lib/python3.6/site-packages/testtools/testcase.py", line 498, in assertThat
    raise mismatch_error
testtools.matchers._impl.MismatchError: 'd1' != ''

Logs
====
- https://logserver.rdoproject.org/openstack-periodic-integration-stable1/opendev.org/openstack/tripleo-ci/master/periodic-tripleo-ci-centos-8-standalone-full-tempest-api-wallaby/bc955f0/logs/undercloud/var/log/tempest/stestr_results.html.gz
- https://logserver.rdoproject.org/openstack-periodic-integration-stable1/opendev.org/openstack/tripleo-ci/master/periodic-tripleo-ci-centos-8-standalone-full-tempest-api-wallaby/6e8b324/logs/undercloud/var/log/tempest/stestr_results.html.gz
https://logserver.rdoproject.org/openstack-periodic-integration-stable1/opendev.org/openstack/tripleo-ci/master/periodic-tripleo-ci-centos-8-standalone-full-tempest-scenario-wallaby/6d5de34/logs/undercloud/var/log/tempest/stestr_results.html.gz