[FIX]purchase:now action_picking_create method returns true

lp bug: https://launchpad.net/bugs/788789 fixed

bzr revid: mma@tinyerp.com-20110830090737-gf4uetngbaet1ku9

addons/purchase/purchase.py

@@ -474,7 +474,7 @@ class purchase_order(osv.osv):
             self.pool.get('stock.move').force_assign(cr, uid, todo_moves)
             wf_service = netsvc.LocalService("workflow")
             wf_service.trg_validate(uid, 'stock.picking', picking_id, 'button_confirm', cr)
-        return picking_id
+        return True
 
     def copy(self, cr, uid, id, default=None, context=None):
         if not default: