Add issubnode to node_types table.

sql/database-create.sql

@@ -716,6 +716,7 @@ CREATE TABLE node_types (
   pxe_boot_path text,
   isvirtnode tinyint(4) NOT NULL default '0',
   isremotenode tinyint(4) NOT NULL default '0',
+  issubnode tinyint(4) NOT NULL default '0',
   PRIMARY KEY  (type)
 ) TYPE=MyISAM;
 

sql/database-migrate.txt

@@ -842,3 +842,8 @@ last_net_act,last_cpu_act,last_ext_act);
        alter table experiments add sync_server varchar(32) \
 		default NULL after idle_ignore;
 
+1.171: Add issubnode slot for dealing with IXP type things.
+
+	alter table node_types add issubnode tinyint(4) NOT NULL default '0' \
+		after isremotenode;
+