add error handling in image capturing in camera

Task-number: QTBUG-28589
Change-Id: Ib3a04038c16beba66f8b8cff85b310dad9a4460a
Reviewed-by: Andy Nichols <andy.nichols@digia.com>

examples/multimediawidgets/camera/camera.h

@@ -72,6 +72,7 @@ private slots:
 
     void toggleLock();
     void takeImage();
+    void displayCaptureError(int, QCameraImageCapture::Error, const QString &errorString);
 
     void configureCaptureSettings();
     void configureVideoSettings();