Ubercart order: "Total cost" field in Views doesn't recognize product quantity

There is a field in Views display of orders called "Total cost" but it doesn't calculate real total cost. It count sum of cost of each single ordered product but not multiplies it by their quantities. This issue was already mentioned for project Ubercart Views 6.x:
#1085830: Ubercart order: Total cost doesn't recognize product quantity
I attached simple patch that fixes the problem.