ST. PETERSBURG,Fla.—Mitt Romney, his friends often say, is a private man in a public world. But with just one month left until the election, he has calculated that to win the presidency he must do what for years he has been loath to: share intimate stories about his life.So it was that as the sun set on his rally here Friday night,...Romney talked about David for the first time himself.“It was clear he was not going to make it,”Romney said. “I went into his room one night when he was in bed,and he asked me a very difficult question. He...