It's no longer needed after removing safemode.

Change-Id: I7581d77a86342e3b6d7c632839f5eb7a5c20902e
Reviewed-on: https://go-review.googlesource.com/c/143397
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>