If xfrm modules cannot be loaded:
- Create netlink.Handle only for ROUTE socket
- Reject local join on overlay secure network
Signed-off-by: Alessandro Boch <aboch@docker.com>
This way we won't vendor test related functions in docker anymore.
It also moves netns related functions to a new ns package to be able to
call the ns init function in tests. I think this also helps with the
overall package isolation.
Signed-off-by: David Calavera <david.calavera@gmail.com>