Lordstown Motors Corp., the electric-truck startup formed specifically to save a shuttered Ohio car factory, has acquired the highly politicized plant from General Motors Co. The acquisition that the two companies plan to announce Thursday ends an era that began when GM opened the complex in 1966. The factory’s fate was largely sealed when the United Auto Workers union was unable to convince GM to keep it in the fold as part of a new labor contact ratified late last month. Terms of the deal aren’t being disclosed.