Reorganize code tree for multiple cisco ML2 mech drivers

[Henry Gessau]

Currently there is one ML2 driver for cisco nexus in

    neutron/plugins/ml2/drivers/cisco

It needs to go down a level so other cisco drivers can live alongside it:

    neutron/plugins/ml2/drivers/cisco/apic
    neutron/plugins/ml2/drivers/cisco/nexus
    neutron/plugins/ml2/drivers/cisco/ucs
    neutron/plugins/ml2/drivers/cisco/...

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/71713

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/71713
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=056942ad5c0b379ebad06110b45b72f685b6c03d
Submitter: Jenkins
Branch: master

commit 056942ad5c0b379ebad06110b45b72f685b6c03d
Author: Henry Gessau <email address hidden>
Date: Thu Feb 6 20:56:00 2014 -0500

    Prepare for multiple cisco ML2 mech drivers

    Code tree reorganization in preparation for ML2 mechanism drivers for
    other cisco products. The cisco nexus ML2 mechanism driver and its
    test cases need to move down into their own subdirectory.

    Closes-bug: #1277222

    Change-Id: I2ba366332276069545b3deb0bbd39016a893327b