Add Support For Open vSwitch

This is a proof of concept. Do Not Merge.

Add support from Open vSwitch

Use the --ovs-enabled flag with the daemon to enable OVS Support
Use --net=ovs when creating a container

ToDo:
- Bump libcontainer revision to include OVS support
- Fix logic for initializing OVS bridge

Signed-off-by: Dave Tucker <dave@dtucker.co.uk>