Tidy up transport delete items

Make the url generation work proerly (though I'm fairly sure we don't
actually need the url as an argument to delete) and remove
debug print statement *blush*

These are no longer used by transport, and nobody else should be using
them.

Note: transport still uses the explicit views

tests broken

byepassing data_layer.handlers, but I think they are
getting in the way of DRF goodness now.