title: UIRefreshControl in tableview dies when try pull to refresh
body: <p>In this class apparently all is in good condition (xcode 10.0), but after i updated to xcode 10.2, every viewController i have the same structure it crashes and now, apparently the app can't recognize the refreshControl when i try pull to refresh.
  Here is a sample code:</p>
  
  <pre><code>class ViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
  
    @IBOutlet weak var tableView: UITableView!
  
    var refresh           : UIRefreshControl!
  
    override func viewDidLoad() {
        super.viewDidLoad()
        self.refresh = UIRefreshControl()
        self.refresh.tintColor = UIColor.red
        self.refresh.attributedTitle = NSAttributedString(string: "Update data")
        self.refresh.addTarget(self, action: #selector(self.refreshMethod), for: .valueChanged)
        self.tableView.addSubview(self.refresh)
    }
  
    @objc func refreshMethod(){
        self.httpGETRequest()
    }
  ...
  }
  </code></pre>