Who would have thought innocuous British author E.L. James would be one to make Hollywood executives bend over backwards to work with her? She’s the writer of “50 Shades of Grey,” a sexually-charged e-book that started as Twilight fan fiction and evolved into its own entity. It’s about Anastasia Steele, a 21-year-old almost-college-grad who starts a steamy S&M relationship with Christian Grey, a billionaire playboy in his late twenties who dominates her…