Vendoring in libnetwork to 3be488927db8d719568917203deddd630a194564

This PR brings the vendored libnetwork code to
3be488927db8d719568917203deddd630a194564, which pulls in quite a few
fixes to support kvstore, windows daemon compilation fixes,
multi-network support for Bridge driver, etc...

Signed-off-by: Madhu Venugopal <madhu@docker.com>