When my sister texted to tell me that Sidney Poitier had passed away, and I started crying. All I could do was conjure up the black and white image of a beloved movie, “A Patch of Blue,” the film that made me fall in love with Poitier. It’s a powerful movie that carries as strong a message about anti-racism as “Guess Who’s Coming To Dinner,” without its political posturing and preachiness. It’s …