http2: fix nits found by vet

Change-Id: I54dbe1ec47e6020d1d34b4f55f1e94c7800f8c12
Reviewed-on: https://go-review.googlesource.com/34874
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

http2/writesched_priority_test.go

@@ -434,7 +434,7 @@ func TestPriorityFlowControl(t *testing.T) {
 			t.Fatalf("Pop(%d)=false, want true", i)
 		}
 		if got, want := wr.DataSize(), 8; got != want {
-			t.Fatalf("Pop(%d)=%d bytes, want %d bytes", got, want)
+			t.Fatalf("Pop(%d)=%d bytes, want %d bytes", i, got, want)
 		}
 	}
 }

http2/writesched_random_test.go

@@ -30,7 +30,7 @@ func TestRandomScheduler(t *testing.T) {
 		t.Fatalf("got %d frames, expected 6", len(order))
 	}
 	if order[0].StreamID() != 0 || order[1].StreamID() != 0 {
-		t.Fatalf("expected non-stream frames first", order[0], order[1])
+		t.Fatal("expected non-stream frames first", order[0], order[1])
 	}
 	got := make(map[uint32]bool)
 	for _, wr := range order[2:] {