fixed undefined function in insert_id() of PostgreSQL driver
diff --git a/system/database/drivers/postgre/postgre_driver.php b/system/database/drivers/postgre/postgre_driver.php
index bfb212c..7989051 100644
--- a/system/database/drivers/postgre/postgre_driver.php
+++ b/system/database/drivers/postgre/postgre_driver.php
@@ -230,7 +230,7 @@
 	 */

 	function insert_id()

 	{

-		$v = version($this->conn_id);

+		$v = $this->_version();

 		$v = $v['server'];

 		

 		$table	= func_num_args() > 0 ? func_get_arg(0) : null;