BUG : Add RegisterPipeline() method to prevent the relabel filter from being destroyed

Modules/Applications/AppSegmentation/app/otbSmallRegionsMerging.cxx

@@ -192,7 +192,7 @@ private:
     }
     
     SetParameterOutputImage("out", changeLabelFilter->GetOutput());
-
+    RegisterPipeline();
     clock_t toc = clock();
 
     otbAppLogINFO(<<"Elapsed time: "<<(double)(toc - tic) / CLOCKS_PER_SEC<<" seconds");