Add another index to linkdelays to improve lookups

sql/database-create.sql

@@ -1181,7 +1181,8 @@ CREATE TABLE linkdelays (
   q_droptail int(11) default '0',
   q_red tinyint(4) default '0',
   q_gentle tinyint(4) default '0',
-  PRIMARY KEY  (node_id,vlan,vnode)
+  PRIMARY KEY  (node_id,vlan,vnode),
+  KEY id (pid,eid)
 ) TYPE=MyISAM;
 
 --

sql/database-migrate.txt

@@ -3296,3 +3296,6 @@ last_net_act,last_cpu_act,last_ext_act);
 
       alter table experiments add index (state);
 
+4.51: Another index to improve lookup in linkdelays.
+
+      alter table linkdelays add index id (pid,eid);