cephadm check-host should verify fsid of ceph.conf
if cephadm check-host detects a ceph cluster(s) running, it can find out the fsid(s) of that cluster (those clusters)
and then it can check /etc/ceph/ceph.conf - the fsid should match one of the detected clusters.
If no match, print an error.
Moved upstream from https://github.com/ceph/ceph-salt/issues/330