In March MDN told you that Canadian midstream giant TransCanada is making a play to buy American Columbia Pipeline Group for $10 billion/C$13 billion (see Rumor Comes True: TransCanada Buying Columbia Pipeline for C$13B). Columbia is a major Marcellus/Utica midstream (i.e. pipelines and processing plants) company. Yesterday Columbia set the date for when its shareholders will vote on the deal. The magic date is June 22…