WASHINGTON (Reuters) - The Guantanamo detainee who told an FBI agent in 2002 that U.S. personnel there had flushed a Koran in a toilet retracted his allegation when questioned this month by military investigators, the Pentagon said on Thursday. "We've gone back to the detainee who allegedly made the allegation and he has said it didn't happen. So the underlying allegation, the detainee himself, within the last two weeks, said that didn't happen," chief Pentagon spokesman Lawrence Di Rita told a briefing. An FBI document, dated Aug. 1, 2002, contained a summary of statements made by the detainee in two...