go.talks/2012/simple: fix bug on test code.

R=adg, r
CC=golang-dev
https://golang.org/cl/13094048
diff --git a/2012/simple/test.go b/2012/simple/test.go
index 88d0c59..0a64c0e 100644
--- a/2012/simple/test.go
+++ b/2012/simple/test.go
@@ -8,10 +8,10 @@
 
 func TestToUpper(t *testing.T) {
 	in := "loud noises"
-	expected := "LOUD NOISES"
+	want := "LOUD NOISES"
 	got := strings.ToUpper(in)
 	if got != want {
-		t.Errorf("ToUpper(%v) = %v, want %v", in, got, expected)
+		t.Errorf("ToUpper(%v) = %v, want %v", in, got, want)
 	}
 }