No performance improvement, but possibly more readable.

Linking juju:
	tip:  real 0m5.470s user 0m6.131s
	this: real 0m5.392s user 0m6.087s

Change-Id: I578e94fbe6c11b19d79034c33b3db31d9689d439
Reviewed-on: https://go-review.googlesource.com/20108Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: David Crawshaw <crawshaw@golang.org>