message: dnn(ocl4dnn/conv): bailout on missing kernel configuration
diff: @@ -379,6 +379,8 @@ bool OCL4DNNConvSpatial<Dtype>::Forward(const UMat& bottom,
  {
  num_ = numImages;
  prepareKernel(bottom, top, weight, bias, numImages);
  + if (bestKernelConfig.empty())
  + return false;
  return convolve(bottom, top, weight, bias, numImages, bestKernelConfig, cv::ocl::Queue::getDefault());
  }
  