Fixed issue inside generated form template

Inside the saveXXXList() method : $con attribute is passed as a
parameter to XXXPeer::doDelete() method, whereas it's not the case for
$obj->save() method. In multiple database connection environment, this
issue can lock tables.

data/generator/sfPropelForm/default/template/sfPropelFormGeneratedTemplate.php

@@ -129,7 +129,7 @@ public function save<?php echo $tables['middleTable']->getPhpName() ?>List($con
         $obj = new <?php echo $tables['middleTable']->getClassname() ?>();
         $obj->set<?php echo $tables['column']->getPhpName() ?>($this->object->getPrimaryKey());
         $obj->set<?php echo $tables['relatedColumn']->getPhpName() ?>($value);
-        $obj->save();
+        $obj->save($con);
       }
     }
   }