undefined method `hostport' for <ip:port> (connected: false):Gearman::Connection

I think

```
message = "Network error on read from #{connection.hostport} while adding job, marking server bad"
```

should be

```
message = "Network error on read from #{connection.to_host_port} while adding job, marking server bad"
```

I don't see `hostport` defined in the `Connection` class
