[FIX] mrp: fix name of leave related to WO

Instead using production name + name of WO as name in the
leave record, use the display name of WO to reprensent uniquely
the leave (even this record is not really reprensent in views).

task-2241471

addons/mrp/models/mrp_production.py

@@ -1099,7 +1099,7 @@ class MrpProduction(models.Model):
 
             # Create leave on chosen workcenter calendar
             leave = self.env['resource.calendar.leaves'].create({
-                'name': self.name + ' - ' + workorder.name,
+                'name': workorder.display_name,
                 'calendar_id': best_workcenter.resource_calendar_id.id,
                 'date_from': best_start_date,
                 'date_to': best_finished_date,

addons/mrp/models/mrp_workorder.py

@@ -730,7 +730,7 @@ class MrpWorkorder(models.Model):
         }
         if not self.leave_id:
             leave = self.env['resource.calendar.leaves'].create({
-                'name': self.production_id.name + ' - ' + self.name,
+                'name': self.display_name,
                 'calendar_id': self.workcenter_id.resource_calendar_id.id,
                 'date_from': start_date,
                 'date_to': start_date + relativedelta(minutes=self.duration_expected),