Dont ping the hub while posting network information

[piyushk]

https://github.com/robotics-in-concert/rocon_multimaster/blob/hydro-devel/rocon_gateway/src/rocon_gateway/gateway_hub.py#L193

Pinging the hub has nothing to do with the local network information being available. This should be broken out in its own separate function and called after publish_network_statistics. In situations where the local network information is not available, but the connection to the hub is alive, this will cause an error

[stonier]

Good point.