nothing at all.....You should do A.M. cardio on an empty stomach....anything in your stomach will be digested and used for engery rather then the fat you already have. You should, however, get some protein and carbs after you cardio session.
L-glutamine does have calories....its an amino acid so it'll have the same amount as any protein (4cal/gram). I'd wait till after cardio to have your glutamine.