UNITED NATIONS, July 19 (Reuters) - Syria barred a U.N. mission to the Middle East unless it excluded one of its members, Norwegian Terje Roed-Larsen, the U.N. adviser on Syria-Lebanon issues, a U.N. official said on Wednesday. Mark Malloch Brown, the deputy secretary-general, told reporters the mission decided not to go to Damascus because it urgently needed to return to New York to brief the U.N. Security Council on a flurry of diplomatic initiatives. "The mission did plan to go to Syria and one of the issues we would have had to grapple with is what to do with Roed-Larsen,"...