WHEN Linda Evangelista gave birth a year ago to son Augustin James, the Canuck covergirl told the Canadian version of Hello! magazine the father was “a New York architect” she wouldn’t name. She may have been fibbing. A source tells us the father is Francois-Henri Pinault, 45, the French head of PPR (Gucci, Yves Saint Laurent) who’s now engaged to Salma Hayek, the mother of his 1-month-old daughter, Valentina Paloma Pinault. PPR didn’t return numerous e-mails and phone calls, but Didier Fernandez of DNA Model Management said, “Not true. She has never said who the father is.”