Adding exception state on the purchase requests

issue5107
review16811002

__init__.py

@@ -7,6 +7,7 @@ from .product import *
 from .purchase_request import *
 from .shipment import *
 from .location import *
+from .purchase import *
 
 
 def register():
@@ -16,12 +17,15 @@ def register():
         PurchaseRequest,
         CreatePurchaseRequestStart,
         CreatePurchaseAskParty,
+        HandlePurchaseCancellationExceptionStart,
         ShipmentInternal,
         CreateShipmentInternalStart,
         Location,
+        Purchase,
         module='stock_supply', type_='model')
     Pool.register(
         CreatePurchaseRequest,
         CreatePurchase,
         CreateShipmentInternal,
+        HandlePurchaseCancellationException,
         module='stock_supply', type_='wizard')