Improve DB version() implementation and add pg_version() support
diff --git a/system/database/drivers/mssql/mssql_driver.php b/system/database/drivers/mssql/mssql_driver.php
index 188c91f..147c634 100644
--- a/system/database/drivers/mssql/mssql_driver.php
+++ b/system/database/drivers/mssql/mssql_driver.php
@@ -339,12 +339,11 @@
 	/**
 	* Version number query string
 	*
-	* @access public
-	* @return string
+	* @return	string
 	*/
-	function _version()
+	protected function _version()
 	{
-		return "SELECT @@VERSION AS ver";
+		return 'SELECT @@VERSION AS ver';
 	}
 
 	// --------------------------------------------------------------------