Fix check for isFocusPointOfInterestSupported to correctly handle iPod Touch 5th Gen

The 5th Gen iPod Touch supports `AVCaptureFocusModeAutoFocus` but not `isFocusPointOfInterestSupported`. It looks like the original check was incorrect: it should not proceed unless the device supports both `AVCaptureFocusModeAutoFocus` *and* `isFocusPointOfInterestSupported`, rather then aborting only if the device supports neither.