WiFiClient.connected() was hanging thinking there was still a connection when the remote had already closed. The one-liner in this patch addresses recv() returning 0 and errno==128. I couldn't find the corresponding errno for 128 but its caught by the case statement which includes EPIPE, ENOTCONN, ECONNRESET and ECONNABORTED so I assume its one of those. Broken pipe maybe?
```c
[D][WiFiClient.cpp:511] connected(): Disconnected: RES: 0, ERR: 128
```
EDIT: added comment to reflect that recv() can set errno when it returns 0.