Perhaps not since Cinderella lost a glass slipper at the ball has there been such a stir about glamorous footwear as there was on Tuesday in Cannes over a report that women had been turned away from a film premiere for failing to wear heels. Social media and the festival gossip circuit lit up after the Screen Daily trade publication reported that a handful of women had been refused entry to Sunday’s premiere of Todd Haynes’s lesbian romance “Carol” for wearing flats.