a few more errors caught by the print checker

R=rsc
CC=golang-dev
https://golang.org/cl/3431046
diff --git a/src/pkg/flag/flag_test.go b/src/pkg/flag/flag_test.go
index abde1e0..4ebb738 100644
--- a/src/pkg/flag/flag_test.go
+++ b/src/pkg/flag/flag_test.go
@@ -196,6 +196,6 @@
 	args := Args()
 
 	if !*before || cmd != "subcmd" || !*after || len(args) != 1 || args[0] != "args" {
-		t.Fatal("expected true subcmd true [args] got %v %v %v %v", *before, cmd, *after, args)
+		t.Fatalf("expected true subcmd true [args] got %v %v %v %v", *before, cmd, *after, args)
 	}
 }