Enable vlan-aware-vms support for Ocata

This patch enables 'trunk' API (vlan-aware-vms) for ML2 backend
engine starting from Ocata release (the feature itself was
implemented in Newton release but had issues with OVS-DPDK before
Ocata).

This change does not affect users not utilizing 'trunk' API (i.e.
enabling the API has no effect on compute-side agents).

Change-Id: Ia46367fc197e10ba7f5b684b035fea86d401e44f
1 file changed