These functions were used in 63a7ccdd23, which was
part of Docker v1.5.0 and v1.6.0, but removed in Docker v1.7.0 when the network
stack was replaced with libnetwork in d18919e304.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit 49de15cdcc)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>