分享功能使用的UIPopoverController在iOS9 过期，替换为popoverPresentationController

记录一下 以备以后用到的时候拿出来看看。
以前使用的：

1 if (UIDevice.currentDevice().userInterfaceIdiom == UIUserInterfaceIdiom.Phone) {
2  presentViewController(vc, animated: true, completion: nil)
3 } else if (popover == nil || !popover!.popoverVisible) {
4                 popover = UIPopoverController(contentViewController: vc)
5              popover!.delegate = self                         popover?.presentPopoverFromRect(inviteView.frame, inView: self.view, permittedArrowDirections: UIPopoverArrowDirection.Any, animated: true) 

现在使用：
 if #available(iOS 8.0, *) {
                vc.modalPresentationStyle = UIModalPresentationStyle.Popover
               vc.popoverPresentationController?.sourceView = inviteView
               vc.popoverPresentationController?.sourceRect = inviteView.bounds
                vc.popoverPresentationController?.permittedArrowDirections = UIPopoverArrowDirection.Any
                 presentViewController(vc, animated: true, completion: nil)
            } else {
                //DeviceUtils.isIOS7()
                if (UIDevice.currentDevice().userInterfaceIdiom == UIUserInterfaceIdiom.Phone) {
                    presentViewController(vc, animated: true, completion: nil)
                } else if (popover == nil || !popover!.popoverVisible) {
                   popover = UIPopoverController(contentViewController: vc)
                    popover!.delegate = self
                   popover?.presentPopoverFromRect(inviteView.frame, inView: self.view, permittedArrowDirections: UIPopoverArrowDirection.Any, animated: true)
               }
               // Fallback on earlier versions
             }