ceph: call update_dentry_lease even when r_locked dir is not set

ceph: call update_dentry_lease even when r_locked dir is not set

We don't really require that the parent be locked in order to update the
lease on a dentry. Lease info is protected by the d_lock. In the event
that the parent is not locked in ceph_fill_trace, and we have both
parent and target info, go ahead and update the dentry lease.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Yan, Zheng <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>