don't fire ErrServerClosed on manually interrupt signals (CTRL/CMD+C)

Former-commit-id: 673c84dd13bb99c0926aa1b4a6b4eff9745403d8

_examples/hero/sessions/main.go

@@ -32,8 +32,5 @@ func main() {
 	// Path: http://localhost:8080
 	app.Get("/", indexHandler)
 
-	app.Run(
-		iris.Addr(":8080"),
-		iris.WithoutServerError(iris.ErrServerClosed),
-	)
+	app.Listen(":8080")
 }