Functional tests are failing during aodhclient import

[Bartłomiej Poniecki-Klotz]

Today during the functional tests run the error occurred:
https://openstack-ci-reports.ubuntu.com/artifacts/c6b/814415/5/check/test-s3api-focal-ussuri/c6b838f/job-output.txt

```
2021-10-25 06:56:18.635402 | bionic-medium | File "/home/ubuntu/src/review.opendev.org/openstack/charm-swift-proxy/.tox/func-target/lib/python3.6/site-packages/aodhclient/utils.py", line 43, in <module>
2021-10-25 06:56:18.635409 | bionic-medium | expr = pp.operatorPrecedence(condition, [
2021-10-25 06:56:18.635416 | bionic-medium | AttributeError: module 'pyparsing' has no attribute 'operatorPrecedence'
```

The issue occurs when aodhclient is imported, because of missing 'operatorPrecedence' from pyparser library.

This library was released during the weekend with version 3.0.0 (https://github.com/pyparsing/pyparsing/blob/master/CHANGES) in which Deprecated features removed of 3.0.0a1 operatorPrecedence is stated.

As a solution, we can use pyparser 2.4.7 (this version works fine) or migrate to 'infixNotation' based on documentation. In the second approach, more adjustment might be needed.

[Aurelien Lourot (aurelien-lourot)]

The functional tests mentioned in the bug description are for the project charm-swift-proxy. Also I heard this issue affects charm-rabbitmq-server too. Re-assigning the bug to these projects.

[Aurelien Lourot (aurelien-lourot)]

The issue is actually in zaza and zaza-openstack-tests. Fixes:
https://github.com/openstack-charmers/zaza/pull/465
https://github.com/openstack-charmers/zaza-openstack-tests/pull/659