Fixed #5932 -- Use `self.pages` and not `self._pages` in `_get_page_range` so...

Fixed #5932 -- Use `self.pages` and not `self._pages` in `_get_page_range` so that an exception is not raised if `self.page_range` is accessed before `self.pages`.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@6702 bcc190cf-cafb-0310-a4f2-bffc1f526a37