Starbucks just makes you think about coffee or other beverages or a quick snack. But that is about to change. It is going to make you think about music. The Starbucks Corp. plans to give away 50 million free digital songs to the customers as a way of promoting a new wireless iTunes music service that’s about to debut in some markets. From Oct. 2 to Nov. 7 they will hand out about 1.5 million…