process port updates in the main loop for mlnx agent

[Irena Berezovsky]

changes the way the Mellanox eswitch agent processes port update
notifications. It does the same for the mlnx-agent as was done for the
ovs-agent in I219c6bdf63b0b5e945b655677f9e28fa591f03cd.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/94882

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/94882
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=fa5eb301dc83f15a30bc40344caca26183147f59
Submitter: Jenkins
Branch: master

commit fa5eb301dc83f15a30bc40344caca26183147f59
Author: Roey Chen <email address hidden>
Date: Sun May 18 11:44:00 2014 +0300

    MLNX Agent: Process port_update notifications in the main agent loop

    This patch changes the way mlnx agent process port_update notifications.
    It does the same for the mlnx agent as was done for the ovs-agent in
    I219c6bdf63b0b5e945b655677f9e28fa591f03cd.
    Processing a port_update notification directly in the RPC
    call may cause competition with the main RPC loop.
    To prevent this problem, the actual process of ports updates is done
    in the main RPC loop, whereas the RPC call merely adds the updated
    port MAC address to a set of updated ports.
    port_update notifications received within a single main loop iteration
    will be coalesced and processed only once.

    Closes-Bug: 1279655
    Change-Id: I63dda60cb3cf171e5e9111a1ecf95e45e1d86362
    Signed-off-by: Roey Chen <email address hidden>