CI:test_live_migration_with_trunk failing frequently on nova-live-migration job

[Amit Uniyal]

tests:
https://9d880f4dac5b6d1509a3-d490a441310dc4e25f1212d07e075dda.ssl.cf1.rackcdn.com/893744/1/check/nova-live-migration/8e97128/testr_results.html
https://291f4451bebc670e507b-a999ae1d5baedde86711d4f3bf719537.ssl.cf1.rackcdn.com/873648/23/check/nova-live-migration/8634c7c/testr_results.html
https://d6c736fcc9a860f59461-fbb3a5107d50e8d0a9c9940ac7f8a1de.ssl.cf5.rackcdn.com/894288/1/check/nova-live-migration/acaf4a4/testr_results.html
https://f0b27972d169a4e6104a-40416aec901d1e1b0fbe6fedfed92f1f.ssl.cf5.rackcdn.com/877446/22/check/nova-live-migration/975e3fc/testr_results.html
https://e19c202f51d149771e8a-51988972a6d6f0f30aafba2bfab9c470.ssl.cf2.rackcdn.com/891289/3/check/nova-live-migration/9812cc6/testr_results.html

Error backtrace:

`
Traceback (most recent call last):
  File "/opt/stack/tempest/tempest/common/utils/__init__.py", line 89, in wrapper
    return func(*func_args, **func_kwargs)
  File "/opt/stack/tempest/tempest/common/utils/__init__.py", line 70, in wrapper
    return f(*func_args, **func_kwargs)
  File "/opt/stack/tempest/tempest/api/compute/admin/test_live_migration.py", line 292, in test_live_migration_with_trunk
    self.assertTrue(
  File "/usr/lib/python3.10/unittest/case.py", line 687, in assertTrue
    raise self.failureException(msg)
AssertionError: False is not true
`