calamari-common: accept OSDMaps that do not contain osd_metadata
calamari-common: accept OSDMaps that do not contain osd_metadata

Fixes: BZ1303241
it seems that cthulhu is crashing when it's been upgraded to look for
osd_metadata but the ceph.py module that includes it in OSDMap has not
yet been distributed to the agent running on the cluster

Signed-off-by: Gregory Meno <4c6f7d69a238d85f14b1affaec7960ea26aa1c6d@redhat.com>

r0h4n/ceph-integration