package/nginx: add upstream CVE-2021-23017 security fix

Fixes the following vulnerability:

- CVE-2021-23017: 1-byte memory overwrite in resolver

For more details, see the advisories:
https://mailman.nginx.org/pipermail/nginx-announce/2021/000300.html
https://www.openwall.com/lists/oss-security/2021/05/25/5



Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
[yann.morin.1998@free.fr: annotate the patch, that it is a backport]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>