Cleanup code so that *most* test work again

Still need to solve the downgrade test

uncloud_net/models.py

@@ -196,11 +196,27 @@ class ReverseDNSEntry(models.Model):
 
     name = models.CharField(max_length=253, null=False)
 
+    @property
+    def reverse_pointer(self):
+        return ipaddress.ip_address(self.ip_address).reverse_pointer
+
+    def implement(self):
+        """
+        The implement function implements the change
+        """
+
+        # Get all DNS entries (?) / update this DNS entry
+        # convert to DNS name
+        #
+        pass
+
+
     def save(self, *args, **kwargs):
         # Product.objects.filter(config__parameters__contains='reverse_dns_network')
         # FIXME: check if order is still active / not replaced
 
         allowed = False
+        product = None
 
         for order in Order.objects.filter(config__parameters__reverse_dns_network__isnull=False,
                              owner=self.owner):
@@ -211,6 +227,7 @@ class ReverseDNSEntry(models.Model):
 
             if addr in net:
                 allowed = True
+                product = order.product
                 break