After the peer is imported via a token, ceph internally stores the
information of the remote cluster. So the rbd-mirror daemon does not
need to have files (key and config) for the remote site.
This means lighter code for us, as well no more restarts for the
rbd-mirror daemon once a peer is added to the configuration.
Signed-off-by: Sébastien Han <seb@redhat.com>