Fix error if odoo lacagette membership is not installed

shifts/models.py

@@ -373,7 +373,12 @@ class CagetteShift(models.Model):
 
     def member_can_have_delay(self, partner_id):
         """ Can a member have a delay? """
-        return self.o_api.execute('res.partner', 'can_have_extension', [partner_id])
+        answer = False
+        try:
+            answer = self.o_api.execute('res.partner', 'can_have_extension', [partner_id])
+        except Exception as e:
+            coop_logger.error("member_can_have_delay : %s", str(e))
+        return answer
 
     def update_counter_event(self, fields):
         """ Add/remove points """