Previously, on machines where /etc/ssl/certs did exist, we'd have this:
$ unset SSL_CERT_DIR
$ unset SSL_CERT_FILE
$ guix pull
Updating channel 'guix' from Git repository at 'https://git.savannah.gnu.org/git/guix.git'...
guix pull: error: Git error: the SSL certificate is invalid
This is because we'd let OpenSSL look for certificates in its default
location, which is an empty directory in its own prefix.
* guix/scripts/pull.scm (honor-x509-certificates): New procedure.
(guix-pull): Use it instead of calling 'honor-lets-encrypt-certificates!'.