message: fix bad assert test, var was not declared
diff: @@ -72,7 +72,7 @@ namespace ospray {
  const size_t numRegions = distribModel->myRegions.size()
  + distribModel->othersRegions.size();
  - beginFrame(dfb);
  + 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);
  