prefix with expiry time

This allows us to feed output to a program like SORT(1) and have
a useful sorting.

main.go

@@ -42,7 +42,7 @@ func main() {
 				log.Printf("get date: %v", err)
 				return
 			}
-			fmt.Printf("%-24v %v\n", res.host, res.exp)
+			fmt.Printf("%v %v\n", res.exp, res.host)
 		}(w)
 	}
 	wg.Wait()