http: remove redundant call to socket.setTimeout()

`Socket.prototype.setTimeout()` clears the previous timer before setting
a new one.

Refs: #25748 (comment)

PR-URL: #25928
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/_http_server.js

@@ -589,7 +589,6 @@ function resOnFinish(req, res, socket, state, server) {
     }
   } else if (state.outgoing.length === 0) {
     if (server.keepAliveTimeout && typeof socket.setTimeout === 'function') {
-      socket.setTimeout(0);
       socket.setTimeout(server.keepAliveTimeout);
       state.keepAliveTimeoutSet = true;
     }