These bind flags were removed by mistake in CL 2167.

Fixes #17921.

Change-Id: I1e8089dade30a212b8db0b216c8299946d924d4b
Reviewed-on: https://go-review.googlesource.com/33271Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>