tools: Use lookup-parent to get ino path

This avoids the need to modify the lookup_ino
response to include the (normally not needed)
parent dentry.

Signed-off-by: John Spray <john.spray@inktank.com>
client/libcephfs: Atomic lookup & ref inode

This is useful for clients that want to do something
(safely) with the inode object they've just retrieved.

Signed-off-by: John Spray <john.spray@inktank.com>
tools: clean up ceph-client-debug

Signed-off-by: John Spray <john.spray@inktank.com>