Minor fixes

[mgood]

Fixed "cell-rundir" getting the last run directory, e.g. for using gun prod output to get Terraform outputs.

Also fixed the "public_ips" output in "host.tf" to aws_instance.host instead of aws_instance.node.

[progrium]

:+1: should we keep this open in case you find more?

[rojaro]

@progrium please merge these patches