```
sshd: Warn about missing ssh-keygen only when necessary
The sshd service is using ssh-keygen to generate missing SSH keys. If
ssh-keygen is missing, it prints the following message:
> /etc/rc.d/sshd: WARNING: /usr/bin/ssh-keygen does not exist.
It makes sense when the key is not generated yet and cannot be created because
ssh-keygen is missing.
The problem is that even if the key is present on the host, the sshd service
would still warn about missing ssh-keygen (even though it does not need it).
```