Fix iOS Sample App
Fix iOS Sample App

Summary:
Encountered when trying to build the sample app on iOS. Seemed `initWithComponentProvider` is now for Swift only and cannot be called in Objective-C.

Change to call `initWithComponentProviderFunc` instead

Reviewed By: passy

Differential Revision: D21629319

fbshipit-source-id: bf39f67ad22259b9c72694e43c507f8869e7bf22

facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper