vfs_ceph_new: Handle absolute path in vfs_ceph_ll_walk

vfs_ceph_new: Handle absolute path in vfs_ceph_ll_walk

It can very well be the case that the incoming path is absolute in
nature which breaks the assumption inside vfs_ceph_ll_walk that it
is within the current working directory. Instead perform a check to
see whether the path includes current working directory path in its
components and accordingly trim it to make it relative in nature.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15818

Signed-off-by: Anoop C S <anoopcs@samba.org>
Reviewed-by: Guenther Deschner <gd@samba.org>
(cherry picked from commit 9341d7fb466c95ea5aa0643049ce2a1f4183b9d0)