store_costing_update

Dropped hub_billing_link table.
Earlier it was pone_hub.estimate <-> hub_billing_link <->
hubq.hubjobs_submitted

Earlier the hub_billing_link table was used as the test hub automated
costing Estimator (H22) was running parallel to the hub Estimator. Now,
the hub automated costing system is integrated with production hub
Estimator (HUB) . Hence, the tables are joined directly.