Fixing executor launch script

* Executor launch script should now start engine because
 it calls engine.convey_task_result() directly. It's a
 temporary solution until engine is a standalone process.
 When it's done executor will be sending a message back to
 engine instead of making a local call.

Change-Id: I4666ca5f1a9cb093e8b7c9e640048f0176955595