LU-9482 hsm: release restore lock without object (part2)

LU-9482 hsm: release restore lock without object (part2)

In the cleanup phase of mdt_hsm_cdt_stop(), there is no need to
recursively unlock the mdt_objects that were to be restored.

Signed-off-by: Quentin Bouget <quentin.bouget@cea.fr>
Change-Id: I4d9212966722d4a2fcecc26210308ea51a200dcd
Reviewed-on: https://review.whamcloud.com/27033
Reviewed-by: Henri Doreau <henri.doreau@cea.fr>
Tested-by: Jenkins
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>