General Motors Co. expects industry vehicle sales to fall short of its original forecast for the year, the latest sign of a slowdown in the U.S. auto market after a record run. GM now expects U.S. light-vehicle sales in the “low” 17-million range, down from an earlier expectation that this year’s tally would roughly match the 17.55-million record from last year, finance chief Chuck Stevens told analysts during a conference call…