slapos_cloud: requesting an instance tree need a project reference

master/bt5/slapos_cloud/SkinTemplateItem/portal_skins/slapos_cloud/InstanceTree_requestPerson.py

@@ -13,5 +13,6 @@ person.requestSoftwareInstance(
   software_type=context.getSourceReference(),
   instance_xml=instance_xml,
   sla_xml=context.getSlaXml(),
-  shared=context.isRootSlave()
+  shared=context.isRootSlave(),
+  project_reference=context.getFollowUpReference()
 )