Bump Go to 1.8.4
Bump Go to 1.8.4

Bumps the Go version used to 1.8.4, which contains security fixes;
https://groups.google.com/forum/#!topic/golang-announce/1hZYiemnkdE

Signed-off-by: Sebastiaan van Stijn <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@gone.nl>

docker/libnetwork,fcrisciani/libnetwork,abhi/libnetwork,mahak/libnetwork,docker/libnetwork,abhi/libnetwork,kolyshkin/libnetwork,mahak/libnetwork,docker/libnetwork,vdemeester/libnetwork,medallia/libnetwork,kolyshkin/libnetwork,mahak/libnetwork,medallia/libnetwork,vdemeester/libnetwork,fcrisciani/libnetwork,vdemeester/libnetwork,kolyshkin/libnetwork,medallia/libnetwork,abhi/libnetwork