
This is the first step to offload VIF plugging code to os-vif library. In particular, this commit moved the veth pair creation from plug_bridge/plug_ovs_hybrid to attach. This makes more sense because the veth pair is created for attach the VIF to container. Partial-Implements: blueprint switch-to-os-vif Change-Id: Ieaeeeac04a0f92207c6235933ca1040da6da3ffe