rolling_update: use ceph health instead of ceph -s

rolling_update: use ceph health instead of ceph -s

The ceph status command returns a lot of information stored in variables
and/or facts which could consume resources for nothing.
When checking the cluster health, we're using the health structure in the
ceph status output.
To optimize this, we could use the ceph health command which contains
the same needed information.

$ ceph status -f json | wc -c
2001
$ ceph health -f json | wc -c
46

Signed-off-by: Dimitri Savineau <dsavinea@redhat.com>