test(integration): fix keys:remove conditional
feat(deisctl): flesh out deisctl client

This is the beginning of an ongoing effort to create a `deisctl`
command for deis clusters. At the moment, it only runs `help` and
`version`, but the groundwork is there to add more commands to the
client.

Note that this client's architecture is heavily influenced by
https://github.com/coreos/fleet/tree/master/fleetctl.