When the film “When Harry Met Sally…” starring Billy Crystal and Meg Ryan, came out in 1989, it was a very funny movie. It still is.So when former Chicago radio personality and stand-up comedian Harry Teinowitz recently came out with his autobiographical play “When Harry Met Rehab,” co-authored with his on-air partner, Spike Manton, you might be tempted to think that it, too, would be a hilarious comedy.Well, it isn’t. Instead, it is an honest, realistic account of what it’s like to be an in-patient at an addiction rehab …