[FIX] ensure active_model and active_ids are setted when opening cancel wizard for Bids

This ensure that in Bid list view "View RFQs/Bids" context values are
correctly set as it defines active_model

Author: yvaucher

purchase_rfq_bid_workflow/model/purchase_order.py

@@ -186,6 +186,8 @@ def action_cancel(self):
                                          'action_modal_cancel_reason'))[1]
         ctx = self._context.copy()
         ctx['action'] = 'action_cancel_ok'
+        ctx['active_model'] = 'purchase.order'
+        ctx['active_ids'] = self.ids
         # TODO: filter based on po type
         return {
             'type': 'ir.actions.act_window',