Murree Brewery, which has managed to survive in a nation in which almost all citizens are forbidden to drink, may get a boost now that Pakistan allows beer exports to non-Muslim countries.RAWALPINDI, Pakistan — In a country where mullahs ceaselessly denounce Western vices and laws prevent restaurants from offering anything stronger than mocktails or Red Bull, the Murree Brewery somehow perseveres, churning out pallets of lager with an efficiency that would make Milwaukee proud.