Capital keeps marching out of Canada’s oil industry, with Kinder Morgan Inc.’s sale of its remaining holdings in the country on Wednesday adding to more than $30 billion of foreign-company divestitures in the past three years. Pembina Pipeline Corp., based in Calgary, is snapping up Kinder’s Canadian assets and a cross-border pipeline in a $3.3 billion deal. For Houston-based Kinder, the deal completes an exit from a country that has frustrated more than a few companies — from ConocoPhillips and Royal Dutch Shell Plc to Marathon Oil Corp.