message: fix gcc-7.2 warning
diff: @@ -72,10 +72,7 @@ namespace ospray {
  const size_t numRegions = distribModel->myRegions.size()
  + distribModel->othersRegions.size();
  - const void *perFrameData = beginFrame(dfb);
  - // This renderer doesn't use per frame data, since we sneak in some tile
  - // info in this pointer.
  - assert(!perFrameData);
  + beginFrame(dfb);
  tasking::parallel_for(dfb->getTotalTiles(), [&](int taskIndex) {
  const size_t numTiles_x = fb->getNumTiles().x;
  