message: fix parent class of denoiser
diff: namespace ospray {
  - struct OSPRAY_MODULE_DENOISER_EXPORT DenoiseFrameOp : public ImageOp {
  + struct OSPRAY_MODULE_DENOISER_EXPORT DenoiseFrameOp : public FrameOp {
  DenoiseFrameOp();
  virtual ~DenoiseFrameOp() override;
  