Support for abortable operations that wait to be aborted

The abortable operations supported by libqmi (NAS Network Scan and WDS Start Network) were not waiting for the command abortion to complete before returning an error, and so, if the response to the operation was received just before the abort request was processed by the device, we would end up with a device that reported a successful result while we assumed the command was actually aborted. This was causing logic errors in WDS Start Network especially, as the client would get reported a failed attempt to start network while the attempt was actually successful.

Fix this, by making these abortable operations wait for the abortion to complete, and if any good response is received before the abortion happens, we would keep the good response instead and cancel the abort request.