Add more service types to avoid salt-minon exception

If ceph-fuse is deployed, a socket named "ceph-client.admin.asok" would appear under
`/var/run/ceph`, and cause current code AttributeError. So this patch will
1) add "client" to the regular expression matching pattern
2) ignore AttributeError from method service_status(), to avoid potential errors in future
Sounds better, and then `service_status()` should return None and  `get_heartbeats()` should check the return value(`service_data` in this case).