[schema] fix BillingAddress permissions: can not use owners in read permission

schema.py

@@ -19,6 +19,8 @@
 
 from yams.buildobjs import RelationDefinition, EntityType, String
 
+from cubicweb.schema import ERQLExpression
+
 from cubes.shoppingcart.schema import ShoppingItem
 from cubes.conference.schema import user_owns_subject,  user_owns_object
 
@@ -36,7 +38,7 @@ class has_shoppingitemtype(RelationDefinition):
 
 class BillingAddress(EntityType):
     __permissions__ = {
-        'read':   ('managers', 'owners',),
+        'read':   ('managers', ERQLExpression('X owned_by U'),),
         'add':    ('managers', 'users',),
         'update': ('managers', 'owners',),
         'delete': ('managers', 'owners',),