Rockdale County signaled its transformation to a blue county as Democrats swept all the local seats except Sheriff, which had a difference of less than 20 votes, and unseated long-time Republican incumbents. Somber faces filled the Whistlepost Tavern in Olde Town Conyers, where Republican candidates and their supporters had gathered while across the highway, at the Lotus Bistro, Democratic candidates and their supporters buzzed with excitement and celebration. About 75 percent of active registered voters in Rockdale, or 38,069, cast their ballots during the weeks leading up to Nov. 6 and on