Add rtabid to nodes table, thus centralizing assignment of rtabids to

vnodes (via their pnode).

sql/database-create.sql

@@ -871,6 +871,7 @@ CREATE TABLE nodes (
   jailip varchar(15) default NULL,
   sfshostid varchar(128) default NULL,
   stated_tag varchar(32) default NULL,
+  rtabid smallint(5) unsigned NOT NULL default '0',
   PRIMARY KEY  (node_id),
   KEY phys_nodeid (phys_nodeid),
   KEY node_id (node_id,phys_nodeid),

sql/database-migrate.txt

@@ -1286,3 +1286,8 @@ last_net_act,last_cpu_act,last_ext_act);
        alter table experiments add delay_osname varchar(20) \
 		default NULL after jail_osname;
 		
+1.124: Add rtabid to nodes table, athough it is meaninful only on a
+       jailed vnode. Set in assign_wrapper.
+
+       alter table nodes add rtabid smallint(5) unsigned NOT NULL \
+		default '0' after stated_tag;