I'm always unccomfortable answering these type of questions because I really don't have a full knowledge of linux and afraid my solution could destroy something. ***Please wait a bit to see if others yell at me for suggesting the following:

I noticed the same error upon upgrading ssh, which I currently only use to gain root access...

ssh -l root localhost

Once logged in I just used "rm /etc/ssh/ssh_config" to end annoying error message. I'm not the kind of person who'd look to see if the config file in question contains anything important, but you might want to be