Revert "Fixed visibility declarations on dbforge and utility classes"

This reverts commit 78a2de4e049f478ec1efd92d639aaf11be933335.
diff --git a/system/database/drivers/oci8/oci8_forge.php b/system/database/drivers/oci8/oci8_forge.php
index c59cfa7..f9a90ff 100644
--- a/system/database/drivers/oci8/oci8_forge.php
+++ b/system/database/drivers/oci8/oci8_forge.php
@@ -55,7 +55,7 @@
 	 * @param	string	the database name
 	 * @return	bool
 	 */
-	public function _drop_database($name)
+	protected function _drop_database($name)
 	{
 		return FALSE;
 	}
@@ -144,7 +144,7 @@
 	 *
 	 * @return	bool
 	 */
-	public function _drop_table($table)
+	protected function _drop_table($table)
 	{
 		return FALSE;
 	}
@@ -166,7 +166,7 @@
 	 * @param	string	the field after which we should add the new field
 	 * @return	object
 	 */
-	public function _alter_table($alter_type, $table, $column_name, $column_definition = '', $default_value = '', $null = '', $after_field = '')
+	protected function _alter_table($alter_type, $table, $column_name, $column_definition = '', $default_value = '', $null = '', $after_field = '')
 	{
 		$sql = 'ALTER TABLE '.$this->db->protect_identifiers($table).' '.$alter_type.' '.$this->db->protect_identifiers($column_name);
 
@@ -212,7 +212,7 @@
 	 * @param	string	the new table name
 	 * @return	string
 	 */
-	public function _rename_table($table_name, $new_table_name)
+	protected function _rename_table($table_name, $new_table_name)
 	{
 		return 'ALTER TABLE '.$this->db->protect_identifiers($table_name).' RENAME TO '.$this->db->protect_identifiers($new_table_name);
 	}
diff --git a/system/database/drivers/oci8/oci8_utility.php b/system/database/drivers/oci8/oci8_utility.php
index bfbf871..f4863c0 100644
--- a/system/database/drivers/oci8/oci8_utility.php
+++ b/system/database/drivers/oci8/oci8_utility.php
@@ -41,7 +41,7 @@
 	 *
 	 * @return	bool
 	 */
-	public function _list_databases()
+	protected function _list_databases()
 	{
 		return FALSE;
 	}
@@ -56,7 +56,7 @@
 	 * @param	string	the table name
 	 * @return	object
 	 */
-	public function _optimize_table($table)
+	protected function _optimize_table($table)
 	{
 		return FALSE; // Is this supported in Oracle?
 	}
@@ -71,7 +71,7 @@
 	 * @param	string	the table name
 	 * @return	object
 	 */
-	public function _repair_table($table)
+	protected function _repair_table($table)
 	{
 		return FALSE; // Is this supported in Oracle?
 	}
@@ -84,7 +84,7 @@
 	 * @param	array	Preferences
 	 * @return	mixed
 	 */
-	public function _backup($params = array())
+	protected function _backup($params = array())
 	{
 		// Currently unsupported
 		return $this->db->display_error('db_unsuported_feature');