Avianca Holdings SA’s chairman and controlling shareholder, German Efromovich, is forcing the Colombian airline into a potential deal with United Continental Holdings Inc. that will hurt minority investors, according to a lawsuit filed Tuesday in New York State Supreme Court. Kingsland Holdings, the second-biggest shareholder in Avianca, is suing the Bogota-based air carrier, Efromovich and Chicago-based United, saying they secretly negotiated an $800 million loan and strategic partnership.