keybase FS quit working

Keybase GUI Version: 1.0.47-20180410052738+f705a9510f

I have Keybase installed on 2 Macs and a Ubuntu VM. On one of my Macs when ever I try to access the keybase FS I get the error:

```bash
$ ls /keybase/public/
ls: /keybase/public/: Device not configured
```

Happens in `/keybase/public/`, `/keybase/private/`, and `keybase/team/` folders.

It works correctly on the Ubuntu VM. I've added a file to my private directory, and everything lists correctly. On my second mac, it lists the files, but the recently added file from the Ubuntu VM doesn't show up.

Start by reproducing the ls failures in /keybase/public/, /keybase/private/, and /keybase/team/ on the affected Mac, then compare them with the working Ubuntu VM and second Mac. Investigate why the Mac reports “Device not configured” and why the second Mac does not show the newly added private file; done means all listed KBFS locations work and synchronized files appear.

Written by the indexing model from the issue text.