ML2 Nexus Automatic vPC config

[Carol Bouchard]

Currently when baremetal event is received, it only reports on ethernet interface. The ML2 Nexus driver additionally checks to see if the user has already configured channel group. If it is configured, the group number is saved away for use with further transaction for this ethernet interface.

This change set takes vPC configuration a step further. If a list of interfaces are provided, then ML2 driver will assume a vPC config is required. If one is already configured, it will use that channel-group; otherwise, a new port channel will be created and use for this interface list.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/472250

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/472250
Committed: https://git.openstack.org/cgit/openstack/networking-cisco/commit/?id=19f1fef013b2afd270c6e400c29653127b41e1a7
Submitter: Jenkins
Branch: master

commit 19f1fef013b2afd270c6e400c29653127b41e1a7
Author: Carol Bouchard <email address hidden>
Date: Thu Jun 8 09:05:08 2017 -0400

    Nexus Baremetal Automated Port Channel Creation

    This codeset implements the ability to automatically create port
    channels for baremetal/ironic transactions when they carry multiple
    ethernet interfaces. Before allocating one, it checks if a port
    channel is already applied on the nexus device by the user.
    If already defined, it uses the port-channel found on the nexus
    device.

    For automated port channels to work, a list of port-channels must
    be provided to ML2 Nexus driver for each switch. A new switch
    config attribute 'vnc_pool=start,end' has been provided in the
    ml2_conf_cisco.ini file for this purpose. This is the list the
    Nexus driver will allocate. The Nexus driver get the list for
    each switch in the baremetal transaction, derive an intersect
    list between them, then select from this derived list.

    Once the initial learning or allocation is performed and Nexus
    device has been configured, the replay operation will persist
    with these values upon switch recovery.

    Limitation: This ability is only supported with the RESTAPI driver.
    The ssh/ncclient driver will no longer support new features.

    Change-Id: I517dba977d39ae533521b33082fe8df9ad58d201
    Closes-bug: #1691822