Clarify the reason for the list truncation
No need for thread
No need for threads
Use create_keypair rather than manually making unrealistic keys
Merge pull request #403 from ClusterHQ/sshkeygen-hang-401

Call ssh-keygen once before transferring keys to nodes

Author: @wallrj
Reviewers: @adamtheturtle, @itamarst

Refs #405

Fixes #401
Merge remote-tracking branch 'origin/master' into key-permissions-382