Fix DBForge index creation on MySQL and CUBRID
diff --git a/system/database/drivers/mysqli/mysqli_forge.php b/system/database/drivers/mysqli/mysqli_forge.php
index 294fc20..5a6560b 100644
--- a/system/database/drivers/mysqli/mysqli_forge.php
+++ b/system/database/drivers/mysqli/mysqli_forge.php
@@ -43,6 +43,16 @@
 	protected $_create_database	= 'CREATE DATABASE %s CHARACTER SET %s COLLATE %s';
 
 	/**
+	 * CREATE TABLE keys flag
+	 *
+	 * Whether table keys are created from within the
+	 * CREATE TABLE statement.
+	 *
+	 * @var	bool
+	 */
+	protected $_create_table_keys	= TRUE;
+
+	/**
 	 * UNSIGNED support
 	 *
 	 * @var	array