mDNS: Fix of text length calculation when detecting a collision

components/mdns/mdns.c

@@ -2147,7 +2147,7 @@ static int _mdns_check_srv_collision(mdns_service_t * service, uint16_t priority
  */
 static int _mdns_check_txt_collision(mdns_service_t * service, const uint8_t * data, size_t len)
 {
-    size_t data_len = 1;
+    size_t data_len = 0;
     if (len == 1 && service->txt) {
         return -1;//we win
     } else if (len > 1 && !service->txt) {