[server/session] remove json dumps around call_service
This backouts changeset b151beea9cb6. With call_service being
in-process and synchronous, there's no RPC use case.
/*
* cubicweb js mock for unit tests
* This module defines variables and functions used in quite a few places
* in cw js framework that can't be used or guessed without a real CW server
*/
var pageid = 'my-page-id';
function _(message) {
return message;
}