message: Fix memory leak with double-duplicate of structured object
diff: @@ -345,7 +345,7 @@ static bool MergeConfigValues(const rdcstr &prefix, SDObject *dstConfig, const S
  ret |= true;
  // if we're copying nodes, do that now
  - dstConfig->DuplicateAndAddChild(srcChild->Duplicate());
  + dstConfig->DuplicateAndAddChild(srcChild);
  }
  }
  