Add seed values support for Query Builder order_by

(feature request #1987)
diff --git a/system/database/drivers/odbc/odbc_driver.php b/system/database/drivers/odbc/odbc_driver.php
index 1710aaf..a01a9d6 100644
--- a/system/database/drivers/odbc/odbc_driver.php
+++ b/system/database/drivers/odbc/odbc_driver.php
@@ -73,6 +73,13 @@
 	 */
 	protected $_like_escape_str = " {escape '%s'} ";
 
+	/**
+	 * ORDER BY random keyword
+	 *
+	 * @var	array
+	 */
+	protected $_random_keyword = array('RND()', 'RND(%d)');
+
 	// --------------------------------------------------------------------
 
 	/**
@@ -85,8 +92,6 @@
 	{
 		parent::__construct($params);
 
-		$this->_random_keyword = ' RND('.time().')'; // database specific random keyword
-
 		// Legacy support for DSN in the hostname field
 		if (empty($this->dsn))
 		{