pkg: fix incorrect prints found by govet

R=golang-dev, nigeltao
CC=golang-dev
https://golang.org/cl/5266041
diff --git a/src/pkg/exp/sql/sql_test.go b/src/pkg/exp/sql/sql_test.go
index 9dca710..eaa0a90 100644
--- a/src/pkg/exp/sql/sql_test.go
+++ b/src/pkg/exp/sql/sql_test.go
@@ -85,7 +85,7 @@
 		if err := stmt.QueryRow(tt.name).Scan(&age); err != nil {
 			t.Errorf("%d: on %q, QueryRow/Scan: %v", n, tt.name, err)
 		} else if age != tt.want {
-			t.Errorf("%d: age=%d, want %d", age, tt.want)
+			t.Errorf("%d: age=%d, want %d", n, age, tt.want)
 		}
 	}