The Major League Soccer summer transfer window opened last week, and Minnesota United supporters should not get their hopes up for big signings to drive fan interest coming out of the FIFA World Cup. The Loons’ leaders pretty much say so themselves. Last week, Chief Executive Officer Shari Ballard said Chief Soccer Officer Khaled El-Ahmad was working to add “a couple of players” before the window closes Sept. 2. El-Ahmad’s goal since joining the…