* hkp_types.go, pgp.go, server.go, worker.go:
  - Implement /pks/hashquery to support SKS recovery & catchup.
    LP: #1197618
Added sks-hashquery utility to determine protocol.
* pgp_types.go, recon.go:
  - Recon recovery makes /pks/hashquery request instead of hget.
    LP: #1044767