create error message when a customer is deleted and already have orders.

Fix #199

core/lib/Thelia/Action/Customer.php

@@ -31,6 +31,8 @@ use Thelia\Core\Event\LostPasswordEvent;
 use Thelia\Core\Event\TheliaEvents;
 use Thelia\Core\Security\SecurityContext;
 use Thelia\Core\Template\ParserInterface;
+use Thelia\Core\Translation\Translator;
+use Thelia\Exception\CustomerException;
 use Thelia\Mailer\MailerFactory;
 use Thelia\Model\ConfigQuery;
 use Thelia\Model\Customer as CustomerModel;
@@ -106,6 +108,10 @@ class Customer extends BaseAction implements EventSubscriberInterface
     {
         if (null !== $customer = $event->getCustomer()) {
 
+            if (true === $customer->hasOrder()) {
+                throw new CustomerException(Translator::getInstance()->trans("Impossible to delete a customer who already have orders"));
+            }
+
             $customer->delete();
         }
     }