WASHINGTON (Reuters) - Civil rights activist Al Sharpton dropped his longshot White House bid on Monday and endorsed John Kerry, saying it was time for the party to rally around the nominee. Sharpton met Kerry for about 30 minutes in the Massachusetts senator's headquarters and emerged to say he was enthusiastically backing Kerry's challenge to President Bush. "I informed him that I think that clearly he has won the nomination, and as I have stated during the race I would support the nominee," Sharpton told reporters after the meeting. "It would be bad strategically and bad for the country to...