gitlab-shell remote IP addresses report HAProxy IP addresses

gitlab-shell now reports the remote IP by extracting it from the SSH_CONNECTION environment variable (gitlab-org/gitlab-shell!399 (merged)), but ideally we'd like to get the actual client IP. There isn't any obvious HTTP headers to get this data from, so I'm not sure if this is possible. I wonder if we can modify the AuthorizedKeysCommand to pass in this information in the environment.

gitlab-sshd will need to be marked as GA before this can be resolved: gitlab-org&5394 (closed)