fix unitialized values warnings
fix unitialized values warnings

closes #490, closes #491, closes #492, closes #493, closes #494.

openfoodfacts/openfoodfacts-server,openfoodfacts/openfoodfacts-server,openfoodfacts/openfoodfacts-server,openfoodfacts/openfoodfacts-server,openfoodfacts/openfoodfacts-server