[l3][port_forwarding] update floating IP (has binding port_forwarding) with empty {} input will lose router_id

[LIU Yulong]

ENV: devstack master

Step to reproduce:
1. create floating IP
2. create port forwarding for that floating IP
3. update floating IP with empty dict:
curl -g -i -X PUT http://controller:9696/v2.0/floatingips/2bb4cc5d-7fae-4c1b-9482-ead60d67abea \
-H "User-Agent: python-neutronclient" -H "Accept: application/json" \
-H "X-Auth-Token: <token>" \
-d '{"floatingip": {}}'

Then this floating IP will turn to a bad status, it can not be managed anymore. Every action on this floating IP will get a neutron-server ERROR log.

Furturemore only updating floating IP qos_policy_id can also result such behavior.
curl -g -i -X PUT http://controller:9696/v2.0/floatingips/2bb4cc5d-7fae-4c1b-9482-ead60d67abea \
-H "User-Agent: python-neutronclient" -H "Accept: application/json" \
-H "X-Auth-Token: <token>" \
-d '{"floatingip": {"qos_policy_id": "d9d3639e-b616-4007-a8fe-52d6154f1eec"}}'

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/613543

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/613543
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=f5842b304c3f24c9cdc8555664155fb4127b0809
Submitter: Zuul
Branch: master

commit f5842b304c3f24c9cdc8555664155fb4127b0809
Author: LIU Yulong <email address hidden>
Date: Fri Oct 26 16:46:57 2018 +0800

    Set router_id if floating IP has port_forwardings

    Set floating IP's router_id when it has port_forwardings
    during the update API.

    Co-Authored-By: chenguobin <email address hidden>

    Closes-Bug: #1799135
    Change-Id: Idb1a52b6f32bdb18d920bce2b891b4d73c557dfb

[OpenStack Infra (hudson-openstack)]

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

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/rocky
Review: https://review.openstack.org/649540

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/649540
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=ef8ecef922edf7d88c851f41ea6acb4651e219a7
Submitter: Zuul
Branch: stable/rocky

commit ef8ecef922edf7d88c851f41ea6acb4651e219a7
Author: LIU Yulong <email address hidden>
Date: Fri Oct 26 16:46:57 2018 +0800

    Set router_id if floating IP has port_forwardings

    Set floating IP's router_id when it has port_forwardings
    during the update API.

    Co-Authored-By: chenguobin <email address hidden>

    Closes-Bug: #1799135
    Change-Id: Idb1a52b6f32bdb18d920bce2b891b4d73c557dfb
    (cherry picked from commit f5842b304c3f24c9cdc8555664155fb4127b0809)

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 13.0.4 release.