release: Remove references to ChallengeResponseAuthentication

[markj]

Summary

This was replaced by KbdInteractiveAuthentication in openssh 8.7, though
ChallengeResponseAuthentication is silently accepted as an alias.
However, this means that the code in ec2.conf which modifies a
commented-out line no longer does anything. Apply a minimal fix.

It may instead be preferable to unconditionally append
"KbdInteractiveAuthentication no" to /etc/ssh/sshd_config instead? I'm
not sure why gce.conf and ec2.conf differ in this way.

[cperciva]

Thanks for catching this!

I don't know why GCE does things differently from EC2 aside from the obvious "code was written by different people who didn't look at each other's work".

[emaste]

Might be worth adding a note to crypto/openssh/FREEBSD-upgrade as well

[markj]

In D34400#779158, @emaste wrote:

Might be worth adding a note to crypto/openssh/FREEBSD-upgrade as well

Perhaps it should go in RELNOTES? There is no entry there for the OpenSSH update. FREEBSD-upgrade doesn't seem to document these sorts of things.

[emaste]

In D34400#779240, @markj wrote:

Perhaps it should go in RELNOTES? There is no entry there for the OpenSSH update. FREEBSD-upgrade doesn't seem to document these sorts of things.

I mean a note to someone who updates OpenSSH in the future to check for new/changed options and update these files. Similar to item 12 "Update nanobsd's copies of the ssh config files"