Bug#976864: openssh-client: fails to parse quoted setting tokens

Package: openssh-client
Version: 1:8.4p1-2~bpo10+1
Severity: normal

Dear Maintainer,

A coworker of mine has stumbled upon a strange inconsistency with ssh
parsing ssh_config.

* What led up to the situation?

An upgrade was performed from v7.9p1-10+deb10u3 to v8.4p1-2~bpo10+1.
Running ssh afterwards failed with the following error:

/etc/ssh/ssh_config line 218: unsupported option

Which references this line of the configuration:

AddKeysToAgent="no"

* What exactly did you do (or not do) that was effective (or
* ineffective)?

Removing the surrounding quotes from the 'no' token.

* What was the outcome of this action?

This allowed the file to be parsed properly, and ssh to work without
issue.

* What outcome did you expect instead?

We expected that the quoted format be accepted.