NSX plugin can't reassociate floating ip to different IP on same port

[Salvatore Orlando]

the NSX plugin is unable to associate a floating IP to a different internal address on the same port where it's currently associated.

How to reproduce:
- create a port with two IPs on the same subnet (just because the fip needs to go through the same router)
- associate a floating IP with IP #1
- associate the same floating IP with IP#2
- FAIL!

This happens with this new test being introduced in tempest: https://review.openstack.org/#/c/71251

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/72485

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/72485
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=8f0f6ca82fcbec153f992fd2347b6c4fd9a9eb25
Submitter: Jenkins
Branch: master

commit 8f0f6ca82fcbec153f992fd2347b6c4fd9a9eb25
Author: Salvatore Orlando <email address hidden>
Date: Mon Feb 10 13:03:08 2014 -0800

    NSX plugin: fix floatingip re-association

    The NSX plugin does not allow to reassociate a floating IP to
    a different internal IP address on the same port where it's
    currently associated.
    This patch fixes this behaviour and adds a unit test to ensure
    re-association on the same port with a different IP is possible.

    A few tweaks to the unit test aux functions were necessary to
    accomodate the newly introduced unit test.

    Change-Id: Iafbc3c54ebc4509ca75155ef138cc6da869df7bd
    Closes-Bug: #1278581