Use select to True on create_date

If the index is created only in __register__ then it is dropped before being
created again.

issue11197
review389881002
(grafted from 4d2ae547c0a2512afea385dfeed074e524eb4c4b)

--HG--
branch : 6.0

sale.py

@@ -282,6 +282,7 @@ class Sale(
     @classmethod
     def __setup__(cls):
         super(Sale, cls).__setup__()
+        cls.create_date.select = True
         cls._order = [
             ('sale_date', 'DESC NULLS FIRST'),
             ('id', 'DESC'),
@@ -364,9 +365,6 @@ class Sale(
         # Migration from 4.0: Drop not null on payment_term
         table.not_null_action('payment_term', 'remove')
 
-        # Add index on create_date
-        table.index_action('create_date', action='add')
-
         # Migration from 5.6: rename state cancel to cancelled
         cursor.execute(*sql_table.update(
                 [sql_table.state], ['cancelled'],