message: apps(model_diagnostics): fix invalid callback
diff: @@ -12,11 +12,14 @@ using namespace cv;
  using namespace dnn;
  -static void diagnosticsErrorCallback(const Exception& exc)
  +static
  +int diagnosticsErrorCallback(int /*status*/, const char* /*func_name*/,
  + const char* /*err_msg*/, const char* /*file_name*/,
  + int /*line*/, void* /*userdata*/)
  {
  - CV_UNUSED(exc);
  fflush(stdout);
  fflush(stderr);
  + return 0;
  }
  static std::string checkFileExists(const std::string& fileName)
  @@ -54,7 +57,7 @@ int main( int argc, const char** argv )
  CV_Assert(!model.empty());
  enableModelDiagnostics(true);
  - redirectError((ErrorCallback)diagnosticsErrorCallback, NULL);
  + redirectError(diagnosticsErrorCallback, NULL);
  Net ocvNet = readNet(model, config, frameworkId);
  