Revert "Fixed visibility declarations on dbforge and utility classes"

This reverts commit 78a2de4e049f478ec1efd92d639aaf11be933335.
diff --git a/system/database/drivers/odbc/odbc_utility.php b/system/database/drivers/odbc/odbc_utility.php
index a07d3b6..d663da1 100644
--- a/system/database/drivers/odbc/odbc_utility.php
+++ b/system/database/drivers/odbc/odbc_utility.php
@@ -41,7 +41,7 @@
 	 *
 	 * @return	bool
 	 */
-	public function _list_databases()
+	protected function _list_databases()
 	{
 		// Not sure if ODBC lets you list all databases...
 		if ($this->db->db_debug)
@@ -61,7 +61,7 @@
 	 * @param	string	the table name
 	 * @return	object
 	 */
-	public function _optimize_table($table)
+	protected function _optimize_table($table)
 	{
 		// Not a supported ODBC feature
 		if ($this->db->db_debug)
@@ -81,7 +81,7 @@
 	 * @param	string	the table name
 	 * @return	object
 	 */
-	public function _repair_table($table)
+	protected function _repair_table($table)
 	{
 		// Not a supported ODBC feature
 		if ($this->db->db_debug)
@@ -99,7 +99,7 @@
 	 * @param	array	Preferences
 	 * @return	mixed
 	 */
-	public function _backup($params = array())
+	protected function _backup($params = array())
 	{
 		// Currently unsupported
 		return $this->db->display_error('db_unsuported_feature');