Fixed #13689 -- Convert the per_page value to an integer upon initialization of the Paginator class to prevent unpleasant TypeErrors. Thanks, rbanffy, Eric Florenzano and Claude Paroz.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16073 bcc190cf-cafb-0310-a4f2-bffc1f526a37