REFAC: need to update the filter after recent refactoring of StreamingShrink

Code/IO/otbMapFileProductWriter.txx

@@ -237,6 +237,7 @@ MapFileProductWriter<TInputImage>
 
       m_StreamingShrinkImageFilter->SetShrinkFactor(sampleRatioValue);
       m_StreamingShrinkImageFilter->SetInput(m_VectorImage);
+      m_StreamingShrinkImageFilter->Update();
 
       m_VectorRescaleIntensityImageFilter = VectorRescaleIntensityImageFilterType::New();
       m_VectorRescaleIntensityImageFilter->SetInput(m_StreamingShrinkImageFilter->GetOutput());