Tacker horizon - VNF Manager doesn't correctly redner VNFs created by vnflcm v1 API

[Hiromu Asahina]

After creating VNF Instance using vnflcm v1 API, tacker-horizon VNF Manager tab becomes not being able to redner the view correctly.

1. Create a VNF Instance according to [1]
2. Access VNF Manager tab in tacker-horizon
3. An error message `Error: Unable to get instances 'vim_name'` appears and any VNFs created aren't displayed.

The cause of this problem is the contents of `placement_attr` that the horizon uses to get `vim_name` have changed in v1 API.
Thus, we have to use `get` method to handle a case where `vim_name` isn't available in `placement_attr`.

[1] https://docs.openstack.org/tacker/latest/user/etsi_vnf_deployment_as_vm_with_user_data.html
[2] https://opendev.org/openstack/tacker-horizon/src/branch/master/tacker_horizon/openstack_dashboard/dashboards/nfv/vnfmanager/tabs.py#L56

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/tacker-horizon/+/817876

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/tacker-horizon/+/817876
Committed: https://opendev.org/openstack/tacker-horizon/commit/1d18379c944fceb56c6367b50c1734e037eee486
Submitter: "Zuul (22348)"
Branch: master

commit 1d18379c944fceb56c6367b50c1734e037eee486
Author: Hiromu Asahina <email address hidden>
Date: Fri Nov 12 22:03:15 2021 +0900

    Fix rendering failure in the VNF Manager tab

    After creating VNF Instance using vnflcm v1 API, tacker-horizon VNF
    Manager tab becomes not being able to redner the view correctly. This
    happens because VNF Manager tab tries to obtain `vim_name` and fails.
    The `vim_name` attribute is no longer available in vnflcm v1 API.

    This patch fix this problem by simply using `get` method to obtain
    `vim_name`.

    Closes-bug: #1950783
    Signed-off-by: Hiromu Asahina <email address hidden>
    Change-Id: If78ffe41dbe3e04cde5678a07df9f55382eb5481

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/tacker-horizon 5.0.0.0rc1 release candidate.