Masakari hostmonitor fails beacuse of missing config

**Bug Report**

What happened:

Hi,

We are trying to implement masakari with hacluster.

After installation and testing the Compute Node HA, there exist ERROR logs on controllers:

"/var/log/kolla/masakari/masakari-wsgi.log":
--------------------------------------------------------
2022-01-31 17:21:51.079 954 INFO masakari.api.openstack.wsgi [req-f9909168-e668-4a97-9752-efe352b3d07e 8e4170ab9f534a2abd04a48b230cf514 0cd27cc3628a4fbeb74a816a11857547 - - -] HTTP excepti
on thrown: Notification received from host r2-osp-test-compute-05.mycompany.dmz of type 'COMPUTE_HOST' is ignored as the host is already under maintenance.
2022-01-31 17:22:46.351 953 ERROR masakari.api.openstack.extensions [req-95361f54-dbb7-4768-8783-e4cccab61968 18c347f36cd74daa9f020b12aee085d2 ba1fc36f5c9c4bbc9fb9647ae0a81b04 - - -] Unexp
ected exception in API method: masakari.exception_Remote.MasakariException_Remote: Failed to fetch notification recovery workflow details for 7e0eec81-e782-4ee7-ad01-fe5f7c4d0fc5
Traceback (most recent call last):

  File "/var/lib/kolla/venv/lib/python3.8/site-packages/masakari/engine/manager.py", line 422, in get_notification_recovery_workflow_details
    self.driver.get_notification_recovery_workflow_details(

  File "/var/lib/kolla/venv/lib/python3.8/site-packages/masakari/engine/drivers/taskflow/driver.py", line 275, in get_notification_recovery_workflow_details
    backend = backends.fetch(PERSISTENCE_BACKEND)

  File "/var/lib/kolla/venv/lib/python3.8/site-packages/taskflow/persistence/backends/__init__.py", line 53, in fetch
    backend, conf = misc.extract_driver_and_conf(conf, 'connection')

  File "/var/lib/kolla/venv/lib/python3.8/site-packages/taskflow/utils/misc.py", line 123, in extract_driver_and_conf
    maybe_uri = conf[conf_key]

TypeError: 'NoneType' object is not subscriptable

During handling of the above exception, another exception occurred:

Traceback (most recent call last):

  File "/var/lib/kolla/venv/lib/python3.8/site-packages/oslo_messaging/rpc/server.py", line 165, in _process_incoming
    res = self.dispatcher.dispatch(message)

  File "/var/lib/kolla/venv/lib/python3.8/site-packages/oslo_messaging/rpc/dispatcher.py", line 309, in dispatch
    return self._do_dispatch(endpoint, method, ctxt, args)

  File "/var/lib/kolla/venv/lib/python3.8/site-packages/oslo_messaging/rpc/dispatcher.py", line 229, in _do_dispatch
    result = func(ctxt, **new_args)

  File "/var/lib/kolla/venv/lib/python3.8/site-packages/masakari/engine/manager.py", line 429, in get_notification_recovery_workflow_details
    raise exception.MasakariException(msg)
--------------------------------------------------------

This issue has similarities with https://bugs.launchpad.net/charm-masakari/+bug/1882656

We have followed that case and resolved this issue after overriding the "masakari.conf" like below:

/etc/kolla/config/masakari.conf
--------------------------------------------------------
[DEFAULT]
notification_driver = taskflow_driver

[taskflow]
connection = mysql+pymysql://masakari:*********@osp-r2-test-internal.mycompany.com:3306/masakari
--------------------------------------------------------

We had to add "notification_driver" to "DEFAULT" section and also added "taskflow" section with DB connection string.

We also had to remove all masakari tables from DB and re-run the "$ masakari-manage db sync" command from the "masakari_api" container.

After that we got the "flowdetails" and other missing DB tables and everything worked.

What you expected to happen: Masakari Installation should work out of the box.

How to reproduce it (minimal and precise): Tried to install hacluster and masakari.

**Environment**:
* OS (e.g. from /etc/os-release): Ubuntu 20.04.2 LTS
* Kernel (e.g. `uname -a`): Linux 5.4.0-90-generic #101-Ubuntu SMP Fri Oct 15 20:00:55 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
* Docker version if applicable (e.g. `docker version`): 20.10.7
* Kolla-Ansible version (e.g. `git head or tag or stable branch` or pip package version if using release): pip installation, kolla-ansible==12.3.0
* Docker image Install type (source/binary): source
* Docker image distribution: DockerHub Images