turn off packetization for loggp bw test

tests/modelnet-p2p-bw-loggp.conf

@@ -9,6 +9,7 @@ LPGROUPS
 }
 PARAMS
 {
+   packet_size="2147483648";
    message_size="128";
    modelnet="loggp";
    net_config_file="logp-param-table.conf";