FLYCTL_OUTPUT_HAR invalid output

[andrewbaxter]

Please only report specific issues with flyctl behavior. Anything like a support request for your application should go to https://community.fly.io. More people watch that space and can help you faster!

Describe the bug
FLYCTL_OUTPUT_HAR=./hars flyctl machines status -a app machine

The generated har file is just

{
    "log": {
        "version": "1.2",
        "creator": {
            "name": "github.com/vvakame/go-harlog",
            "version": "0.0.1"
        },
        "entries": null
    }
}

It has no info, and Chrome rejects it because entries is null.

The same goes for machine stop etc.

This happens on the latest published release as well as on source master (checked out a minute ago).