Fix: Removed delete of orders with amount is 0.

htdocs/comm/propal.php

htdocs/commande/fiche.php

htdocs/compta/commande/fiche.php

htdocs/compta/facture.php

htdocs/fourn/commande/fiche.php

htdocs/fourn/facture/fiche.php

htdocs/install/upgrade2.php

htdocs/langs/en_US/main.lang

htdocs/langs/fr_FR/main.lang

htdocs/langs/it_IT/main.lang

htdocs/langs/pt_PT/main.lang

mysql/tables/llx_commandedet.sql