Value of network's is_default is incorrect in create

[Hongbin Lu]

Description
===========
Create a network with '--default' option, the network was created and the 'is_default' attribute was shown as 'True'. However, the 'is_default' attribute was actually not set because it is for external network only.

Reproduce
=========
$ openstack network create --default testnet
+---------------------------+--------------------------------------+
| Field | Value |
+---------------------------+--------------------------------------+
...
| is_default | True |
...
+---------------------------+--------------------------------------+

$ openstack network show testnet
+---------------------------+--------------------------------------+
| Field | Value |
+---------------------------+--------------------------------------+
...
| is_default | None |
...
+---------------------------+--------------------------------------+

Expected
========
The response of the create command should have 'is_default' set to None

Actual
======
The response of the create command have 'is_default' set to True

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/538331

[zhaobo (zhaobo6)]

I don't think it is a valid bug. Please see
http://specs.openstack.org/openstack/neutron-specs/specs/mitaka/get-me-a-network.html

[Akihiro Motoki (amotoki)]

is_default is a boolean attribute, so I think "None" is a reasonable solution.

On the other hand, it is confusing. For a short term solution, I see the following solutions:
- Neutron returns an exception if is_default==True is specified for a network with router:external==False.
- OSC raise an error before sending a request if --default is specified for a non-external network (--internal option)

[Akihiro Motoki (amotoki)]

For a short term solution, I think adding a check to OSC sounds better, as a change in neutron response needs a micro-versioning from the perspective of API-SIG but it still take time (at least in Rocky).

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/539303

[OpenStack Infra (hudson-openstack)]

Change abandoned by Hongbin Lu (<email address hidden>) on branch: master
Review: https://review.openstack.org/538331
Reason: Fixed in: https://review.openstack.org/#/c/511983/

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/python-openstackclient 5.1.0 release.