pagination warning

Fix issue producing some warning due to undeclared variables in pagination.php override:

Notice: Undefined variable: class_start in /var/www/2013/joomla2.5.8_bootstrap/templates/h5bptb/html/pagination.php on line 96
Notice: Undefined variable: class_start in /var/www/2013/joomla2.5.8_bootstrap/templates/h5bptb/html/pagination.php on line 96