[gate] Dead code elimination
[gate] Dead code elimination

Using __rpc_register_queue makes unnecessary any old reference to
__rpc_requests_in_progress, which makes all more confusing.

Signed-off-by: Simone Libutti <7dbd3541d180fb2293c2d424b6ba631d047e4733@ibtsystems.it>

thingsboard/thingsboard-gateway,thingsboard/thingsboard-gateway