HAVANA — Tropical Storm Erika dissipated early Saturday, even as its remnants began drenching parts of eastern Cuba. But it left devastation in its path, killing at least 20 people and leaving another 31 missing on the small eastern Caribbean island of Dominica, authorities said. In Haiti, one person died in a mudslide just north of Port-au-Prince, and at least four others were killed in a traffic accident that apparently occurred in the rain. The U.S.