All of the pieces to handle IPv6 are now in place. Add IPv6-specific
code wrapped in the proper #ifdef's so that IPv6 support works when
it's enabled at build-time.
Reviewed-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve Dickson <steved@redhat.com>