[OVN] Remove dependency on port_object

[zhanghao]

The 'update_port' and 'delete_port' method currently depend on ‘port_object’, which was added to keep things backward compatible.

The‘port_object’ needs to be removed in the future versions. Currently, qos, security groups, and dns still depend on it.Therefore, the qos、security groups and dns need to be unbound from 'port_object' before it can be removed.

[1]https://opendev.org/openstack/neutron/src/branch/master/neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/ovn_client.py#L459
[2]https://opendev.org/openstack/neutron/src/branch/master/neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/ovn_client.py#L731

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/708806

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/709540

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/710554

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/709540
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=25817782646a52b622cd732a43bffb123bcbf6f9
Submitter: Zuul
Branch: master

commit 25817782646a52b622cd732a43bffb123bcbf6f9
Author: zhanghao <email address hidden>
Date: Wed Jan 29 13:05:55 2020 -0500

    [OVN] Remove SG dependency on original port dict

    The 'port_object' needs to be removed, so the current security group
    dependency on it needs to be resolved first. The 'security_group_ids'
    has been stored in the 'external_ids' of the logical switch port. When
    updating or deleting a port, the security groups can be obtained directly
    from 'ovn_port'.

    Change-Id: I764f3426fe0e38094b77b69f4cb752d042f4d701
    Partial-Bug: #1863987

[OpenStack Infra (hudson-openstack)]

Change abandoned by "Rodolfo Alonso <email address hidden>" on branch: master
Review: https://review.opendev.org/c/openstack/neutron/+/708806
Reason: Superseded by https://review.opendev.org/c/openstack/neutron/+/711317

[OpenStack Infra (hudson-openstack)]

Change abandoned by "Rodolfo Alonso <email address hidden>" on branch: master
Review: https://review.opendev.org/c/openstack/neutron/+/710554
Reason: Please, feel free to restore the patch, address the comments and rebase the patch.