receiveSynAck() not able to come out of the blocking call, when it receive TCP reset packet.

I tried to ping golang.org 

```
$ sudo ./latency -i ppp0 golang.org
Measuring round-trip latency from 27.57.134.157 to golang.org on port 80
```

but the in receiveSynAck(), application is not able to read the bytes from the conn : 

```
numRead, _, err := conn.ReadFrom(buf)
```
