Use hkps://keys.openpgp.org as the default keyserver

Use hkps://keys.openpgp.org as the default keyserver

As of 2.2.17, GnuPG will refuse to accept any third-party
certifications from OpenPGP certificates pulled from the keyserver
network.

The SKS keyserver network currently has at least a dozen popular
certificates which are flooded with enough unusable third-party
certifications that they cannot be retrieved in any reasonable amount
of time.

The hkps://keys.openpgp.org keyserver installation offers HKPS,
performs cryptographic validation, and by policy does not distribute
third-party certifications anyway.

It is not distributed or federated yet, unfortunately, but it is
functional, which is more than can be said for the dying SKS pool.
And given that GnuPG is going to reject all the third-party
certifications anyway, there is no clear "web of trust" rationale for
relying on the SKS pool.

One sticking point is that keys.openpgp.org does not distribute user
IDs unless the user has proven control of the associated e-mail
address.  This means that on standard upstream GnuPG, retrieving
revocations or subkey updates of those certificates will fail, because
upstream GnuPG ignores any incoming certificate without a user ID,
even if it knows a user ID in the local copy of the certificate (see
https://dev.gnupg.org/T4393).

However, we have three patches in
debian/patches/import-merge-without-userid/ that together fix that
bug.

Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
(cherry picked from commit 59e8aac9d6f2ee322a753373013032bbb13e3eb3)

Gbp-Pq: Topic keyserver-cleanup
Gbp-Pq: Name Use-hkps-keys.openpgp.org-as-the-default-keyserver.patch