- Remove NOT NULL constraint from creator_person_id in case the   creator is deleted.
- Remove NOT NULL constraint from creator_person_id in case the
  creator is deleted.


dreibh/planetlab-lxc-plcapi,dreibh/planetlab-lxc-plcapi,dreibh/planetlab-lxc-plcapi,dreibh/planetlab-lxc-plcapi