ipv4: remove unnecessary control message marshaling

The encoded data is just for debugging at kernel side and has remained
in normal code path until now, oops.

Change-Id: I28003ae211eb63d717d7e20f39ee0f39201892a5
Reviewed-on: https://go-review.googlesource.com/31534
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
1 file changed