Flintrock gets terribly slow if known_hosts is big

[douglaz]

• Flintrock version: master
• Python version: 3.4.3
• OS: Ubuntu

So slow that it's unable to create a cluster with more than a couple of machines.

This seems to be a paramiko issue (paramiko/paramiko#191), must it's something flintrock's users and developers should be aware.

Perhaps there is a workaround for that? At least a warning would be helpful to avoid lots of wasted hours trying to figure out why flintrock is behaving so weird in an old machine.

[nchammas]

Hmm, I wonder if Flintrock even needs to read from known_hosts. If not, we can presumably just turn that off via an option to Paramiko.