Update class-rewrite.php

FIXES 404 error for pagination with custom 'page' query var

See: http://wordpress.org/support/topic/plugin-wp-no-category-base-wpml-compatible-solution-to-fix-category-pagination-404-error

I am having pagination issues (404) using a theme that changes the 'pagination_base' field of 'wp_rewrite' together with Yoast SEO configured to suppress the base category. This patch solves the issue.