Fix bogus use of BIO_sock_should_retry.

Reviewed-by: NAndy Polyakov <appro@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3948)

apps/s_socket.c

@@ -215,7 +215,7 @@ int do_server(int *accept_sock, const char *host, const char *port,
         if (type == SOCK_STREAM) {
             do {
                 sock = BIO_accept_ex(asock, NULL, 0);
-            } while (sock < 0 && BIO_sock_should_retry(ret));
+            } while (sock < 0 && BIO_sock_should_retry(sock));
             if (sock < 0) {
                 ERR_print_errors(bio_err);
                 BIO_closesocket(asock);