Director Djo Tunda Wa Munga talks about his film “Viva Riva!” It’s a thriller about Congolese gas gangsters, set in Kinshasa, a city inundated with war, crime, corruption, food and energy shortages, and crushing poverty. “Viva Riva!”  won six awards at the 2011 African Movie Academy Awards, including best film, and it opens June 10 at Angelika Film Center.