ceph: add ceph_has_realms_with_quotas() check to ceph_quota_update_statfs()

ceph: add ceph_has_realms_with_quotas() check to ceph_quota_update_statfs()

When MDS rejects a session, remove_session_caps() ->
__ceph_remove_cap() -> ceph_change_snap_realm() clears
i_snap_realm for every inode that loses its last cap.
The realm is restored once caps are re-granted after
reconnect. It is not a real error and this patch changes
pr_err_ratelimited_client() on doutc().

Every quota methods ceph_quota_is_max_files_exceeded(),
ceph_quota_is_max_bytes_exceeded(),
ceph_quota_is_max_bytes_approaching() calls
ceph_has_realms_with_quotas() check. This patch adds
the missing ceph_has_realms_with_quotas() call into
ceph_quota_update_statfs().

[ idryomov: add braces around both arms of multiline ifs ]

Signed-off-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Reviewed-by: Alex Markuze <amarkuze@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>