ML2 Cisco Nexus MD: Enhance update_port processing

[Rich Curran]

Port this change in the cisco plugin, https://review.openstack.org/#/c/50389/ (Detect and process live-migration in Cisco plugin) to ML2. Changes under this bug were made to the cisco plugin update_port() method.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/78774

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/78774
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=5e8043e8a2675b4485a52d688ea86d1165d81a29
Submitter: Jenkins
Branch: master

commit 5e8043e8a2675b4485a52d688ea86d1165d81a29
Author: Rich Curran <email address hidden>
Date: Thu Mar 6 16:26:27 2014 -0500

    ML2 Cisco Nexus MD: VM migration support

    Add VM (live) migration support to the ML2 cisco nexus mechanism driver.

    Change-Id: I8be2fc1f020ef1fc6c19daba0a9e278629046016
    Closes-Bug: #1247976