Set passwords to known values for rcord pod

Change-Id: I891008befc0fdbca42deaf3619e03b59f920c83e
diff --git a/onlab.yml b/onlab.yml
index 872649e..eabdc84 100644
--- a/onlab.yml
+++ b/onlab.yml
@@ -55,6 +55,10 @@
     aliases:
       - head
 
+password_compute_node: ubuntu
+password_maas_admin: admin
+password_maas_user: cord
+
 # Inventory for ansible, used to generate inventory.ini
 inventory_groups:
   config: