NullQuota driver returns None that breaks client API

[Jakub Libosvar]

When NullQuotaDriver is used, any operations above quotas return None instead of empty dict. Some tools rely on the quota, like for example following fails:

openstack quota show admin
'NoneType' object has no attribute 'items'

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/neutron/+/827875

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/neutron/+/827875
Committed: https://opendev.org/openstack/neutron/commit/8ccbbb229276c62de4799810571b222d9bc046f5
Submitter: "Zuul (22348)"
Branch: master

commit 8ccbbb229276c62de4799810571b222d9bc046f5
Author: Jakub Libosvar <email address hidden>
Date: Fri Feb 4 10:15:12 2022 -0500

    [quota] Enable ``DbQuotaDriverNull`` as a production driver

    Enabled ``DbQuotaDriverNull`` as a productio quota database
    quota driver. This driver does not enforce any quota nor have access
    to the database. When using this quota driver, the API will return
    the default empty values expected from the ``QuotaDriverAPI`` class.

    Closes-bug: #1960032

    Change-Id: Iafa24753e657746a8b8165b5a63c17de9a9ba791
    Signed-off-by: Jakub Libosvar <email address hidden>
    Co-Authored-By: Rodolfo Alonso Hernandez <email address hidden>

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 21.0.0.0rc1 release candidate.