message: info: fix warning
  We need to reserve one char for null termination.
diff: @@ -100,11 +100,11 @@ void InfoImpl::process_autopilot_version(const mavlink_message_t &message)
  product.vendor_id = autopilot_version.vendor_id;
  const char *vendor_name = vendor_id_str(autopilot_version.vendor_id);
  - STRNCPY(product.vendor_name, vendor_name, sizeof(product.vendor_name));
  + STRNCPY(product.vendor_name, vendor_name, sizeof(product.vendor_name - 1));
  product.product_id = autopilot_version.product_id;
  const char *product_name = product_id_str(autopilot_version.product_id);
  - STRNCPY(product.product_name, product_name, sizeof(product.product_name));
  + STRNCPY(product.product_name, product_name, sizeof(product.product_name - 1));
  set_product(product);
  }
  