One Convergence Neutron Plugin Implementation

One Convergence Neutron Plugin implements Neutron API to provide a network
virtualization solution. The plugin works with One Convergence NVSD controller
to provide the functionality. This checkin implements the Neutron core APIs
and the plugin will be extended to support the L3 and service plugin extension
APIs.

Change-Id: Ic8a0dc0f5950d41b9b253c0d61b6812dbfd161c7
Implements: blueprint oc-nvsd-neutron-plugin
Merge "One Convergence Neutron Plugin Implementation"