Uniformize way to report error after "buildoc" action.

htdocs/comm/askpricesupplier/card.php

htdocs/comm/propal.php

htdocs/commande/card.php

htdocs/compta/facture.php

htdocs/contrat/card.php

htdocs/expedition/card.php

htdocs/expensereport/card.php

htdocs/fourn/commande/card.php

htdocs/fourn/facture/card.php

htdocs/livraison/card.php

htdocs/projet/card.php

htdocs/projet/tasks/task.php