Fixes #3529: only allow nodes with valid UUID
Merge pull request #17 from fanf/bug_3523/only_accept_node_id_with_valid_uuid

Fixes #3529: only allow nodes with valid UUID
Merge branch 'branches/rudder/2.4' into branches/rudder/2.5

* branches/rudder/2.4:
  Fixes #3529: only allow nodes with valid UUID