GAZA (Reuters) - Palestinian militants burst into a Gaza City mourning tent set up for Yasser Arafat on Sunday and fired shots in protest at the presence of his moderate successor Mahmoud Abbas, but he was unhurt, witnesses said. They said a Palestinian security man was fatally wounded in an exchange of fire between militants and bodyguards shielding Abbas, also known as Abu Mazen. He was on a visit to accept condolences for the Palestinian president, who died on Thursday. The chaos erupted after masked gunmen from Arafat's faction-ridden Fatah movement shouting "No to Abu Mazen," a critic of violence,...