fix #728 dropNativeClient null ptr

Author: Links2004

src/WebSocketsClient.cpp

@@ -786,9 +786,9 @@ void WebSocketsClient::handleHeader(WSclient_t * client, String * headerLine) {
                     }
                     // falls through
                 case 403:    ///< Forbidden
-                    // todo handle login
-                    // falls through
-                default:    ///< Server dont unterstand requrst
+                             // todo handle login
+                             // falls through
+                default:     ///< Server dont unterstand requrst
                     ok = false;
                     DEBUG_WEBSOCKETS("[WS-Client][handleHeader] serverCode is not 101 (%d)\n", client->cCode);
                     clientDisconnect(client);

src/WebSocketsServer.cpp

@@ -516,6 +516,9 @@ void WebSocketsServerCore::messageReceived(WSclient_t * client, WSopcode_t opcod
  * @param client WSclient_t *  ptr to the client struct contaning the native client "->tcp"
  */
 void WebSocketsServerCore::dropNativeClient(WSclient_t * client) {
+    if(!client) {
+        return;
+    }
     if(client->tcp) {
         if(client->tcp->connected()) {
 #if(WEBSOCKETS_NETWORK_TYPE != NETWORK_ESP8266_ASYNC) && (WEBSOCKETS_NETWORK_TYPE != NETWORK_ESP32)