trunk: can not delete bound trunk for agent which allow create trunk on bound port

[Le, Huifeng]

High level description:
For agent such as linux bridge which allows creating trunk on bound port, it is not allowed to delete the trunk if not unbound the port (parent-port) first. It will break the use scenario which expect to keep the port's (trunk's parent port) communication while delete the trunk.
The issue can be reproduced on the latest devstack.

Environments:configure to use linux bridge agent
Version: latest devstack

Steps to reproduce:
1. create network/subnet/trunk parent port/trunk sub port
openstack network create net0
openstack subnet create --network net0 --subnet-range 10.0.4.0/24 subnet0
openstack port create --network net0 trunk1_port
parent_trunk1_mac="$( openstack port show trunk1_port | awk '/ mac_address / { print $4 }' )"
openstack port create --network net1 --mac-address "$parent_trunk1_mac" trunk1_subport1
result: success

2. create VM (bound trunk parent port first)
openstack server create --flavor ds512M --image vlan-capable-image --nic port-id="$trunk1_port_id" --wait vm_trunk1
result: success

3. create trunk: openstack network trunk create --parent-port trunk1_port --subport port=trunk1_subport1,segmentation-type=vlan,segmentation-id=101 trunk1
result: success

4. delete trunk:
openstack network trunk delete trunk1
Expected output: success
Actual output: fail with message "Trunk trunk1 is currently in use"

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/605589

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/615792

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/605589
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=6b5466969499de021275c49e3fec2ab45d7fd908
Submitter: Zuul
Branch: master

commit 6b5466969499de021275c49e3fec2ab45d7fd908
Author: Huifeng Le <email address hidden>
Date: Thu Sep 27 21:43:35 2018 +0800

    Enable delete bound trunk for linux bridge agent

    For agent such as linux bridge which allows creating trunk on
    bound port, this patch provides a fix to allow deleting trunk
    without unbound port first. And it will help to keep the port
    (trunk's parent port) working while deleting the trunk.

    Co-Authored-By: Allain Legacy <email address hidden>

    Closes-Bug: #1794424
    Story: 2003889

    Change-Id: Iae2ae535bf3ba1548136bf3fe4306a42bad4e635

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/615792
Committed: https://git.openstack.org/cgit/openstack/neutron-tempest-plugin/commit/?id=1c9f40b96b7ae2722ef39e10e73a22ecab454c6c
Submitter: Zuul
Branch: master

commit 1c9f40b96b7ae2722ef39e10e73a22ecab454c6c
Author: Huifeng Le <email address hidden>
Date: Wed Nov 7 01:14:21 2018 +0800

    Add scenario test for trunk E2E flow

    Add Scenario test "test_parent_port_connectivity_after_trunk_deleted"
    to verify the E2E flow of fix proposed for Bug: #1794424
    "Enable delete bound trunk for linux bridge agent"

    Co-Authored-By: Allain Legacy <email address hidden>

    Depends-On: https://review.openstack.org/#/c/605589/
    Change-Id: Ic2e02f4b5dc8d7930e251340d8be194733b0a4f7
    Related-Bug: #1794424
    Story: 2003889

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 14.0.0.0b1 development milestone.