changing function fb_social_url to point on the front page

like this:

function fb_social_url($url = NULL){
if(drupal_is_front_page()){
return url(NULL, array('absolute' => TRUE, 'alias' => $aliased ));
}else{
$aliased = variable_get('fb_social_urls_mode', 0);
return url($url, array('absolute' => TRUE, 'alias' => $aliased ));
}
}