message: samples: don't call twice of VideoCapture::open()
diff: @@ -20,7 +20,7 @@ int main(int, char**)
  //--- INITIALIZE VIDEOCAPTURE
  VideoCapture cap;
  // open the default camera using default API
  - cap.open(0);
  + // cap.open(0);
  // OR advance usage: select any API backend
  int deviceID = 0; // 0 = open default camera
  int apiID = cv::CAP_ANY; // 0 = autodetect default API
  