Closing server prot_listener socket after stream setup failure (#1084)

Making sure the server closes prot_listener socket at the end of a session with a client. Without this change the socket may remain open, for example when there is a failure during the UDP stream establishment because the --window value is too high. Closing the socket was added to cleanup_server() as it seems to handle all cases where the socket may remain open.

src/iperf_server_api.c

@@ -377,6 +377,9 @@ cleanup_server(struct iperf_test *test)
     if (test->listener) {
 	close(test->listener);
     }
+    if (test->prot_listener > -1) {     // May remain open if create socket failed
+	close(test->prot_listener);
+    }
 
     /* Cancel any remaining timers. */
     if (test->stats_timer != NULL) {