Don't user "debug" mode for iperf3

wrapper.py

@@ -291,7 +291,7 @@ for key, i in enumerate(sender):
         utility_args['port'], i['port'],                        \
         utility_args['ipv6'] ]
     if args.utility == "iperf3":
-        i['utility_command'] += [ "-J", "-d"]
+        i['utility_command'] += [ "-J"]
     if args.utility == "netperf":
         i['utility_command'] += [ "--", "-k", "all", "-P", i['src_port'] ]
     i['utility_command'] += [ utility_args['congestion'], i['congestion'] ]