Add new column to switch_stack_types - supports_private . It can be

dangerous to create private VLANs on switches with certain features
enabled (like the experimental net), so we'll use this column to
safeguard against any accidents.

sql/database-create.sql

@@ -863,6 +863,7 @@ CREATE TABLE switch_paths (
 CREATE TABLE switch_stack_types (
   stack_id varchar(10) NOT NULL default '',
   stack_type varchar(10) default NULL,
+  supports_private tinyint(1) NOT NULL default '0',
   PRIMARY KEY  (stack_id)
 ) TYPE=MyISAM;