By Ewan Murray Aston Villa finish their pre-season preparations this Saturday when they travel to Germany to play Borussia Dortmund in a friendly. The Villans have been busy in the transfer market ahead of an exciting Champions League campaign but that hasn’t translated to pre-season success. While they enjoyed two early victories over lesser opposition, Unai Emery’s side then lost three games on the bounce before their recent 3-2 win over Athletic Club. It’s been a mixed bag for the Midlands club. Borussia Dortmund find themselves in a similar position. They have won just once in pre-season a…