When you consider all the care and taste and politics and planning that go into the yearly execution of the Cannes Film Festival , you’d think that coming up with a tasty and satisfying opening-night film — a movie that delights, or at least pleases, the festival audience, stoking its appetite for the treasures to come — would not require the French equivalent of rocket science. The opening-night selection needn’t be the best film in the festival; it hardly needs to be a major film. But surely it should be an inviting one.    Yet there’s a strange karma that clings to the Cannes opener. Simply put: It’s rarely very good, and often a semi-washout, to the point that there almost seems to be an underlying design to this particular programming choice, as if the festival wanted us to feel, “Okay!…