Open Radar

 
Summary:
Trying to add a custom `NSURLProtocol` to a `NSURLSessionConfiguration` `protocolClasses` crashes at runtime.

Steps to Reproduce:
Add this to a storyboard:
/// Where RecordingProtocol is just a subclass of `NSURLProtocol`
        RecordingProtocol.registerClass(RecordingProtocol)
        let configuration = self.defaultSessionConfiguration()
        configuration.protocolClasses?.insert(RecordingProtocol.self, atIndex: 0)
        
        return configuration

Expected Results:
Custom protocol gets added to the configuration instance and app keeps running.

Actual Results:
Protocol never gets added to the configuration instance and instead crashes with the following error:
```
fatal error: NSArray element failed to match the Swift Array Element type
error: warning: got name from symbols: _XCDidPauseInDebugger
error: assigning to 'void *' from incompatible type 'BOOL' (aka 'signed char')
error: 1 errors parsing expression
```

Regression:
This was possible in `Swift 1.x` (see http://github.com/esttorhe/Rec which holds a working function using `Swift 1.x`