Law School - Adding notice on Booklist page

Law School courses textbooks are listed only on the [Law School website](https://www.law.berkeley.edu/php-programs/courses/allCourseBooks.php); Law students currently see a blank space on the booklist page. Added a notice with a link to where they can find their textbook information.

![screen shot 2014-10-10 at 2 23 38 pm](https://cloud.githubusercontent.com/assets/7464841/4599259/cd779a4e-50c3-11e4-9ed4-e201a284051a.png)
@christianv Sure thing! I'll do that now.