src, misc: applied gofmt -s -w

Pending CL 113120043.

LGTM=dave
R=golang-codereviews, dave
CC=golang-codereviews
https://golang.org/cl/112290043
diff --git a/src/pkg/bufio/bufio_test.go b/src/pkg/bufio/bufio_test.go
index 76d3c8e..be43a80 100644
--- a/src/pkg/bufio/bufio_test.go
+++ b/src/pkg/bufio/bufio_test.go
@@ -438,7 +438,7 @@
 	if err != nil {
 		t.Error("unexpected error on ReadRune (2):", err)
 	}
-	for _ = range buf {
+	for range buf {
 		_, err = r.ReadByte()
 		if err != nil {
 			t.Error("unexpected error on ReadByte (2):", err)