sshd would not start (another 8.x grudge)

[Mikhail T.]

The sshd would not start after the upgrade from 7.x to 8.1 on one of the 
systems:

    Starting sshd.
    cipher_encrypt: bad plaintext length 553
    /etc/rc.d/sshd: WARNING: failed to start sshd

Archiving the 3-year old /etc/ssh/ssh_host_rsa_key and having it 
recreated solved the immediate problem, but the connecting clients 
weren't happy about it...

If anyone is interested, the old ssh_host_rsa_key is available by direct 
e-mail.

    -mi