Increase transaction counter when erasing party

As the erase is done using direct SQL query, the counter is not increased so
there is no log event created because the wizard use the counter to determine
if there were some modification and thus create a log entry.

Closes #13002
(grafted from c1f76346bda026970d8f964f7198dd55e4c1cdc7)

--HG--
branch : 7.0

modules/party/party.py

@@ -1071,7 +1071,8 @@ class Erase(Wizard):
     def transition_erase(self):
         pool = Pool()
         Party = pool.get('party.party')
-        cursor = Transaction().connection.cursor()
+        transaction = Transaction()
+        cursor = transaction.connection.cursor()
 
         resources = self.get_resources()
         parties = replacing = [self.ask.party]
@@ -1124,6 +1125,7 @@ class Erase(Wizard):
                                         Model.__name__ + ',%')
                                     & resource_field.sql_id(
                                         table.resource, Model).in_(query)))
+        transaction.counter += 1
         return 'end'
 
     def check_erase(self, party):