Avoid resetting start_date.

The first one found is just good enough.

master/bt5/vifib_slap/SkinTemplateItem/portal_skins/vifib_slap/Person_getOpenOrderDifference.xml

@@ -94,8 +94,10 @@ for start_date_tuple in start_date_tuple_list:\n
   if start_date_tuple[0] in hosting_subscription_mapping:\n
     line_id = hosting_subscription_mapping[start_date_tuple[0]]\n
     line = previous_open_sale_order[line_id]\n
-    if line.getStartDate() != start_date:\n
+    if line.getStartDate() is None:\n
       modify_kw_kw[line.getAggregate(portal_type=\'Hosting Subscription\')] = {\'start_date\': start_date}\n
+    # reset start_date to possibly already set up on Open Order Line\n
+    start_date = line.getStartDate()\n
   elif start_date_tuple[0] in add_kw_kw:\n
     add_kw_kw[start_date_tuple[0]][\'start_date\'] = start_date\n
   hs = portal.restrictedTraverse(start_date_tuple[0])\n

master/bt5/vifib_slap/bt/revision

-672
\ No newline at end of file
+673
\ No newline at end of file