ROME, April 15 (Reuters) - An Italian hostage killed in Iraq was hailed on Thursday as a hero who in his last moments told his kidnappers defiantly: "I'm going to show you how an Italian dies." Fabrizio Quattrocchi, one of four Italian security guards abducted earlier this week, was shot dead on Wednesday after Italy refused to bow to the kidnappers' demands and withdraw some 3,000 troops stationed in Iraq. Italian Foreign Minister Franco Frattini said a video recording of the killing showed that Quattrocchi was hooded when his kidnappers put a gun to his head. "When the murderers were...