quickfix for setting layout info only when available (review tomorrow)

src/storm-dft/storage/dft/DFTBuilder.cpp

@@ -91,8 +91,10 @@ namespace storm {
 
             // Set layout info
             for (auto& elem : mElements) {
+                if(mLayoutInfo.count(elem.first) > 0) {
                     dft.setElementLayoutInfo(elem.second->id(), mLayoutInfo.at(elem.first));
                 }
+            }
 
             return dft;
         }