CLSA-2026-1777950533 openssh: Fix of CVE-2026-3497

CVE-2026-3497: fix information disclosure / DoS in GSSAPI key exchange by initialising gssbuf, recvtok, msgtok to GSSCEMPTYBUFFER and replacing non-terminating sshpktdisconnect with sshpacketdisconnect in kexgssc.c / kexgsss.c...