Missing versioned notification examples in Python 3

[Takashi Natsume]

Python 3 is used in executing 'tox -e docs' by default currently.
When Python 3 is used, there are some missing notification examples.

In python 3, map function returns an iterator instead of a list,
and importlib.import_module(*1) is not executed in the document generation.
So it causes missing versioned notification examples in the nova docs.

*1: https://github.com/openstack/nova/blob/4ea64cad3fcc4897690bfb2c02d2b06d65db4dcf/doc/ext/versioned_notifications.py#L59-L61

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/579436

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/579436
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=54d3e7096ca3b68af3cf5f0d30f7c0949e87c6d9
Submitter: Zuul
Branch: master

commit 54d3e7096ca3b68af3cf5f0d30f7c0949e87c6d9
Author: Takashi NATSUME <email address hidden>
Date: Mon Jul 2 13:59:19 2018 +0900

    Fix missing versioned notification examples

    Python 3 is used in executing 'tox -e docs' by default currently.
    When Python 3 is used, there are some missing notification examples.

    In python 3, map function returns an iterator instead of a list,
    and importlib.import_module is not executed in the document generation.
    So it causes missing versioned notification examples in the nova docs.

    This patch fixes it.

    Change-Id: Ie4f3f9be0ca7f94ce00a14f3d825a067a807eb12
    Closes-Bug: #1779606

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/nova 18.0.0.0b3 development milestone.