SearchControllerBug

Leak caused by UISearchController on iOS10

Steps to reproduce

• Lauch app on iOS 10
• Tap "next view" button on the intial view.
• Tap to activate seach bar
• Tap back button (while keyboard is still up)

Note that [ViewController2 dealloc] is never called.

Below is the memory graph of the app after ViewController2 is dismissed.