go/types: revert gofmt -s change to permit building with 1.3

Per request from dsymonds.

Change-Id: I1f034859880df0d8313d67da90457ac56459ed76
Reviewed-on: https://go-review.googlesource.com/2562
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: David Symonds <dsymonds@golang.org>

go/types/initorder.go

@@ -137,7 +137,7 @@ func (check *Checker) reportCycle(cycle []*objNode, i int) {
 	obj := cycle[i].obj
 	check.errorf(obj.Pos(), "initialization cycle for %s", obj.Name())
 	// print cycle
-	for range cycle {
+	for _ = range cycle {
 		check.errorf(obj.Pos(), "\t%s refers to", obj.Name()) // secondary error, \t indented
 		i++
 		if i >= len(cycle) {