Even Bill Cosby can make mistakes. Conan writer Josh Comers and comedian Jeff Cosgrave (“Lopez Tonight”) join me to talk about a classic fumble, “Leonard Part 6.” Go to itunes! After Cosby saw how bad this film was he went around telling people not to see it. Way to be honest. But at some point you must have known it was going pear shape. We recorded on May Day and there were protests right outside the studio. We talk like there were a million people, but from the pictures you…