a few more errors caught by the print checker

R=rsc
CC=golang-dev
https://golang.org/cl/3431046

src/pkg/archive/tar/reader_test.go

@@ -136,7 +136,7 @@ testLoop:
 			break
 		}
 		if hdr != nil || err != nil {
-			t.Errorf("test %d: Unexpected entry or error: hdr=%v err=%v", i, err)
+			t.Errorf("test %d: Unexpected entry or error: hdr=%v err=%v", i, hdr, err)
 		}
 		f.Close()
 	}

src/pkg/archive/tar/writer_test.go

@@ -141,7 +141,7 @@ testLoop:
 			}
 		}
 		if err := tw.Close(); err != nil {
-			t.Errorf("test %d: Failed closing archive: %v", err)
+			t.Errorf("test %d: Failed closing archive: %v", i, err)
 			continue testLoop
 		}
 

src/pkg/flag/flag_test.go

@@ -196,6 +196,6 @@ func TestChangingArgs(t *testing.T) {
 	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)
 	}
 }