meta: use canonical KEYURL location
meta: use canonical KEYURL location

Follow the HTTP redirects and use the canonical location for the SSH
key.

  1) "ceph.com/git" -> "git.ceph.com"
  2) http -> https

The purpose of this change is to reduce the strain on the ceph.com web
server (and use a secure connection as well).

ceph/downburst,ceph/downburst