Updates golang_org/x/net/lif to rev 084869a for:
- lif: rename internal types and constants generated by cgo

Change-Id: Icf478d60f5ef35800966c62dcf046f7fe50204ff
Reviewed-on: https://go-review.googlesource.com/30731
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>