modify patch to test if patch_hash exists before creating it

cosmogramme/sql/patch/patch_234.php

 <?php
 $adapter = Zend_Registry::get('sql');
-$adapter->query('CREATE TABLE `patch_hash` ( '
+$adapter->query('CREATE TABLE  IF NOT EXISTS `patch_hash` ( '
 								. 'id int(11) unsigned not null auto_increment,'
 								. '`value` char(40) not null,'
 								. 'primary key (id),'