my modification of instruction does not work

Used theme – Flavor of Industrial Themes.

Instead replacing <?php the_permalink(); ?> with <?php if (function_exists('mbj_link_blog_link_url_display')) { mbj_link_blog_link_url_display(); } ?> as it is told in step 3 of the Installation instruction I tried to modify function the_permalink() directly in link-template.php substituting the following code

echo apply_filters('the_permalink', get_permalink());

with

if (function_exists('mbj_link_blog_link_url_display')) {
		mbj_link_blog_link_url_display(); }
	else {
		echo apply_filters('the_permalink', get_permalink()); }

Unfortunately I see no effect.

http://wordpress.org/extend/plugins/link-blog/