[CLI] "keybase pgp (push|pull)-private" fails with "file does not exist"

I've updated my primary key since my previous one expired and now, whenever I try `keybase pgp push-private` or `keybase pgp pull-private` it fails with the following error:

> ERROR file does not exist

Looking at my private files, there is a `.keys/pgp` with some files under my private folder.

Reproduce the failure with `keybase pgp push-private` and `keybase pgp pull-private` after updating the primary key, then inspect the `.keys/pgp` files under the private folder and the code handling these CLI commands. Done means both commands locate the current private key and no longer report `file does not exist`.

Written by the indexing model from the issue text.