kuryr-libnetwork did not clean neutron port when use existed neutron network

[Liping Mao]

Problem:
when user use existed neutron network, kuryr-libnetwork will not delete the neutron port which is created for containers.

Reproduce Steps:
1. create neutron network and subnet
2. create kuryr network with this existed neutron network.
3. run a container, and delete the container.

Expect Result:
the neutron port which created from container is deleted after the container is deleted.

Actual Result:
the neutron port did not delete.

When ipamdriver release address, it will find the subnet according to poolid. This will assume the subnet need has subnetpool-id. When "existed neutron network" case, the network and subnet is pre-created by EndUser, which do not have subnetpool-id. and subnetpool-id is unchangable after the subnet is created. This will cause kuryr can't release the neutron port.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/412772
Committed: https://git.openstack.org/cgit/openstack/kuryr-libnetwork/commit/?id=4af7e1cdd821bbda0319251f1aae633a04573413
Submitter: Jenkins
Branch: master

commit 4af7e1cdd821bbda0319251f1aae633a04573413
Author: Dongcan Ye <email address hidden>
Date: Tue Dec 20 14:20:57 2016 +0800

    Delete port created by kuryr

    In current code, we get the port's subnet by checking the
    subnet's subnetpool_id equal with the given PoolID, but in
    existing environment, the subnet may lack subnetpool_id,
    hence we will not get the port's subnet and leaves the
    kuryr-libnetwork port undeleted.

    This patch checks the port's device owner and determines
    the given POOL's subnet_id and ip_address is equal to
    port's fixed_ips attribute.

    Change-Id: I736adbb2409b50a5e11d3aa7d31778944cfdeae1
    Co-Authored-By: Liping Mao <email address hidden>
    Closes-Bug: #1651015