message: samples: videocapture_camera use VideoCapture with 0 index
  Not all backends support -1 index.
diff: @@ -11,7 +11,7 @@ int main(int, char**)
  {
  Mat frame;
  cout << "Opening camera..." << endl;
  - VideoCapture capture(-1); // open the first available camera
  + VideoCapture capture(0); // open the first camera
  if (!capture.isOpened())
  {
  cerr << "ERROR: Can't initialize camera capture" << endl;
  