This commit adds support for OpenDaylight as an ML2 MechanismDriver. The
ODL MechanismDriver does not need an agent since ODL itself handles
programming bridges, tunnels, and ports on the host.
Implements bp ml2-opendaylight-mechanism-driver
Change-Id: Ic1612cd3e8efd39e74a7ed8cff28e91b1f388971