Credential locks are not released

[Samuel Allan]

When running tempest tests with a test_accounts_file, it very quickly runs out of accounts, resulting in InvalidCredentials errors with "Insufficient number of users provided.":

```
setUpClass (murano_tempest_tests.tests.scenario.application_catalog.test_security_groups.TestSecurityGroups)
------------------------------------------------------------------------------------------------------------

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

      File "/lib/python3.10/site-packages/tempest/test.py", line 206, in setUpClass
    raise value.with_traceback(trace)

      File "/lib/python3.10/site-packages/tempest/test.py", line 196, in setUpClass
    cls.setup_clients()

      File "/lib/python3.10/site-packages/murano_tempest_tests/tests/scenario/application_catalog/base.py", line 48, in setup_clients
    creds = cls.get_configured_isolated_creds(type_of_creds='primary')

      File "/lib/python3.10/site-packages/murano_tempest_tests/tests/scenario/application_catalog/base.py", line 107, in get_configured_isolated_creds
    creds = cls.credentials.get_primary_creds()

      File "/lib/python3.10/site-packages/tempest/lib/common/preprov_creds.py", line 315, in get_primary_creds
    net_creds = self._get_creds()

      File "/lib/python3.10/site-packages/tempest/lib/common/preprov_creds.py", line 272, in _get_creds
    free_hash = self._get_free_hash(useable_hashes)

      File "/lib/python3.10/site-packages/oslo_concurrency/lockutils.py", line 414, in inner
    return f(*args, **kwargs)

      File "/lib/python3.10/site-packages/tempest/lib/common/preprov_creds.py", line 219, in _get_free_hash
    raise lib_exc.InvalidCredentials(msg)

    tempest.lib.exceptions.InvalidCredentials: Invalid Credentials
Details: Insufficient number of users provided. TestRepositorySanity,ServerActionsTestJSON,TestVersioningNegative,BulkNetworkOpsTest,TestEnvironmentTemplatesSanity,TestRepositorySanity,TestRepository,TestCinderVolumes,TestServices,TestEnvironmentTemplates,TestMuranoDeployment,TestCinderVolumeIsolatedAdmin have allocated all the credentials for this allocation request
```

It appears that locks are not released, as the account lock files (names are hashes, content is test class name) in /tmp/tempest-lock/ remain there after a test run is complete.

This may be related to https://bugs.launchpad.net/tempest/+bug/1455561 - it was marked as fixed, but some users later post comments with workarounds, suggesting there are remaining related issues.

[Samuel Allan (samuelallan)]

I can reliably reproduce this failure to clean up credentials on my environment with this test:

```
murano_tempest_tests.tests.api.application_catalog.artifacts.test_repository.TestRepositorySanity.test_get_list_packages[id-2818aaa0-6613-4bd9-8abe-02713121357a,smoke]
```

Which I believe is found in git+https://opendev.org/openstack/murano-tempest-plugin.git@2.6.0

In my environment (2023.2/stable sunbeam), this test is skipped with a message:

```
{3} setUpClass (murano_tempest_tests.tests.api.application_catalog.artifacts.test_repository.TestRepositorySanity) ... SKIPPED: Murano is not using GLARE backend. Skipping GL
```

Every time I run tempest with this test, I see another file left in the /tmp/tempest-lock directory, such that after 4 runs, the directory looks like this:

```
root@tempest-k8s-0:/tmp/tempest-lock# grep -r .
533bd1b808f1c89a41790ccb98b31610:TestRepositorySanity
7b03fe17fc92437c7bb7dff60b8bf565:TestRepositorySanity
e5604fdc3b6b8200b13a1bfa6c4bf8fa:TestRepositorySanity
22a805d5d9f003ab3342b9af2401528a:TestRepositorySanity
```

These files accumulate regardless of whether other tests run in the same tempest run or not (eg. running with --regex smoke or running with --regex 'murano_tempest_tests..*artifacts.test_repository.TestRepositorySanity').

These lock files that aren't cleaned up accumulate, and eventually cause tempest to fail to allocate accounts for tests.

[Samuel Allan (samuelallan)]

So far the only tests that are triggering the failed credential lock cleanup are within the murano plugin. I'm wondering if it's related to https://bugs.launchpad.net/tempest/+bug/1846236 , as this plugin also raises skipException in the resource_setup methods.

For example, here is where skipException is raised for the example in the previous comment: https://opendev.org/openstack/murano-tempest-plugin/src/commit/e16b2dc1512854c9a249944a5f288a1065f328fd/murano_tempest_tests/tests/api/application_catalog/artifacts/test_repository.py#L29-L34