keybase login fails on Windows with TypeError: Request path conatins unescaped characters

```
> keybase login
warn: No config file found; tried 'C:\Users\XXXX\AppData\Roaming\keybase\config.json'
Your keybase username or email: XXXXX
Your keybase login passphrase: XXXXX
_http_client.js:73
throw new TypeError('Request path contains unescaped characters.');
^
TypeError: Request path contains unescaped characters.
at new ClientRequest (_http_client.js:73:11)
at TunnelingAgent.exports.request (http.js:49:10)
at TunnelingAgent.createSocket (C:\Users\XXXXX\AppData\Roaming\npm\node_modules\keybase\node_modules\request\node_modules\tunnel-agent\index.js:117:25)
at TunnelingAgent.createSecureSocket [as createSocket] (C:\Users\XXXXX\AppData\Roaming\npm\node_modules\keybase\node_modules\request\node_modules\tunnel-agent\index.js:184:41)
at TunnelingAgent.addRequest (C:\Users\XXXXX\AppData\Roaming\npm\node_modules\keybase\node_modules\request\node_modules\tunnel-agent\index.js:80:8)
at new ClientRequest (_http_client.js:154:16)
at Object.exports.request (http.js:49:10)
at Object.exports.request (https.js:136:15)
at Request.start (C:\Users\XXXXX\AppData\Roaming\npm\node_modules\keybase\node_modules\request\request.js:583:30)
at Request.end (C:\Users\XXXXX\AppData\Roaming\npm\node_modules\keybase\node_modules\request\request.js:1237:28)
```

Windows 7 x64
I sit behind a proxy, but exported the settings into environment variables. Installation worked pretty well with this.

Start with the `keybase login` entry point and reproduce the failure on Windows 7 with the proxy environment variables set. Read the stack trace through `_http_client.js`, `request.js`, and `tunnel-agent/index.js`; done means login completes without the unescaped-request-path TypeError.

Written by the indexing model from the issue text.