It’s been 10 years since Daniel Radcliffe, Emma Watson and Rupert Grint first hopped on the Hogwarts Express, and the three have done little else since. Now that the ride will soon come to an end, the cast is trying to fathom a life without the Harry Potter films — an understandable difficulty, considering that they’ve grown up along with their characters. The other item showing its age is the storyline of the sixth installment, “Harry Potter and the Half-Blood Prince.” Part humor and part horror with a healthy dose of hormones, “Half-Blood Prince” is clearly more attuned for an audience who, like the cast, are no longer in grade school
