[ADD] test that  cancel an existing demo PO and create a new revision
[ADD] test that  cancel an existing demo PO and create a new revision

andrius-preimantas/purchase-workflow,juschaef/purchase-workflow,xpansa/purchase-workflow,open-synergy/purchase-workflow,xpansa/purchase-workflow,Endika/purchase-workflow,acsone/purchase-workflow,lepistone/purchase-workflow,andrius-preimantas/purchase-workflow,acsone/purchase-workflow,Endika/purchase-workflow,Endika/purchase-workflow,juschaef/purchase-workflow,andrius-preimantas/purchase-workflow,juschaef/purchase-workflow,factorlibre/purchase-workflow,lepistone/purchase-workflow,lepistone/purchase-workflow,Antiun/purchase-workflow,open-synergy/purchase-workflow,Antiun/purchase-workflow,acsone/purchase-workflow,factorlibre/purchase-workflow,open-synergy/purchase-workflow,factorlibre/purchase-workflow,xpansa/purchase-workflow,Antiun/purchase-workflow