Fixing SQL error : "DELETE FROM $table_class_user WHERE user_id = '".$user_id."" see #5836

main/inc/lib/usermanager.lib.php

@@ -282,8 +282,9 @@ class UserManager {
         }
 
         // Unsubscribe user from all classes
-        $sql = "DELETE FROM $table_class_user WHERE user_id = '".$user_id."'";
-        Database::query($sql);
+        //Classes are not longer supported
+        /*$sql = "DELETE FROM $table_class_user WHERE user_id = '".$user_id."'";
+        Database::query($sql);*/
 
         // Unsubscribe user from usergroup_rel_user
         $sql = "DELETE FROM $usergroup_rel_user WHERE user_id = '".$user_id."'";