security/openvpn-devel: upgrade port to git commit efad93d049 (2023-11-17)

contains a number of bugfixes and minor improvements, plus fixes
for two bugs that have been assigned CVEs:

• CVE-2023-46850 OpenVPN versions between 2.6.0 and 2.6.6 incorrectly use a send buffer after it has been free()d in some circumstances, causing some free()d memory to be sent to the peer. All configurations using TLS (e.g. not using --secret) are affected by this issue. (found while tracking down CVE-2023-46849 / Github #400, #417)

• CVE-2023-46849 OpenVPN versions between 2.6.0 and 2.6.6 incorrectly restore "--fragment" configuration in some circumstances, leading to a division by zero when "--fragment" is used. On platforms where division by zero is fatal, this will cause an OpenVPN crash.

see also https://community.openvpn.net/openvpn/wiki/SecurityAnnouncements

Also adjust files/patch-tests__t_cltsrv.sh because upstream commit
d623aa6c29 conflicts with this patch.

Security: 2fe004f5-83fd-11ee-9f5d-31909fb2f495
Security: CVE-2023-46849
Security: CVE-2023-46850
(cherry picked from commit 110af6a7bee600b9382fd568beecb28593378df4)