fixes #701, use the appropriate site_id instead of 1

When coming from the album edit page with the action link to synchronization

admin/cat_modify.php

@@ -361,7 +361,7 @@ else
   {
     $template->assign(
       'U_SYNC',
-      $base_url.'site_update&site=1&cat_id='.$category['id']
+      $base_url.'site_update&site='.$category['site_id'].'&cat_id='.$category['id']
       );
   }