bug#46829: Fresh install of 1.2.0 can't guix pull

[Leo Famulari]

On Wed, Mar 17, 2021 at 03:36:44PM +0100, Ludovic Courtès wrote:
>   (define (honor-x509-certificates store)
>     "Use the right X.509 certificates for Git checkouts over HTTPS."
>     (unless (honor-system-x509-certificates!)
>       (honor-lets-encrypt-certificates! store)))
> 
> By default, 1.2.0 installs ‘nss-certs’, so I would assume such
> installations are unaffected, right?

So, the bug here is that `guix pull` is using the wrong certificate
store. It should use le-certs, but is instead ignoring le-certs, and
looking for a system-wide store that doesn't exist.

I tested with an installer image from current master, and the bug still
exists.