cid#1700582: silence Unchecked return value from library

Change-Id: Ie4ff636f0b1da6a9e0209c4b9193e29b5a743950
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/210279
Tested-by: Jenkins
Reviewed-by: Xisco Fauli <xiscofauli@libreoffice.org>

uui/source/iahndl-oauth2.cxx

@@ -202,7 +202,7 @@ void SAL_CALL OAuth2Request::Impl::listenHTTP(void* pThis)
 
         beast::flat_buffer buffer;
         http::request<http::string_body> req;
-        http::read(socket, buffer, req, ec);
+        (void)http::read(socket, buffer, req, ec);
         if (ec)
         {
             SAL_WARN("ucb.ucp.cmis", "HTTP read failed: " << ec.message());