mon: add the initial mon keyring to the mon store
mon: add the initial mon keyring to the mon store

Once we have our first monitor up and running we need to add it to the
monitor store as a safety measure. Just in case the local file gets
deleted and you need to add a new monitor. Now you can retrieve this key
like this:

ceph config-key get initial_mon_keyring > initial_mon_keyring.txt

Signed-off-by: Sébastien Han <62d754cc350e84d3b1c32ae79f976f5348e74a40@redhat.com>

WingkaiHo/ceph-ansible,font/ceph-ansible,albertomurillo/ceph-ansible,travmi/ceph-ansible,bengland2/ceph-ansible,ceph/ceph-ansible,albertomurillo/ceph-ansible,font/ceph-ansible,fgal/ceph-ansible,albertomurillo/ceph-ansible,travmi/ceph-ansible,fgal/ceph-ansible,bengland2/ceph-ansible,jtaleric/ceph-ansible,WingkaiHo/ceph-ansible,jtaleric/ceph-ansible,ceph/ceph-ansible,WingkaiHo/ceph-ansible