Joyent provider uploads user's private ssh key by default

[Tim Penhey]

By default, the joyent provider uploads the user's private ssh key. We shouldn't do this.

We should default to registering a new ssh key and have one for the sole purpose of dealing with joyent.

[Marc Deslauriers (mdeslaur)]

This is CVE-2015-1316

[Nate Finch (natefinch)]

We can't really register a new key with joyent (we'd have to authenticate with joyent in order to upload our generated key... it's kind of a chicken and egg problem).

I think the best answer is just to do what we do with the rest of the providers -you need to have the auth in the config file, and we return an error if it's not there.