It appears to be a trivial dreg. Unreferenced. Gone.

Change-Id: I4a5ceed48e84254bc8a07fdb04487a18a0edf965
Reviewed-on: https://go-review.googlesource.com/20122
Run-TryBot: Rob Pike <r@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>