peerdiscovery: flush stop socket if not stopping

src/peer_discovery.cpp

@@ -250,7 +250,10 @@ PeerDiscovery::listener_thread(PeerDiscoveredCallback callback)
         }
 
         if (data_coming > 0) {
-            if (FD_ISSET(stop_readfd, &readfds)) { break; }
+            if (FD_ISSET(stop_readfd, &readfds)) {
+                std::array<uint8_t, 64 * 1024> buf;
+                recv(stop_readfd, buf.data(), buf.size(), 0);
+            }
 
             std::array<uint8_t,dht::InfoHash::size() + sizeof(in_port_t)> data_receive;
             size_t data_receive_size = data_receive.size();