all: use a more straightforward return value

all: use a more straightforward return value

Change-Id: I27e86c221da7f541c4823f501801e02942c9a829
Reviewed-on: https://go-review.googlesource.com/c/go/+/649935
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>