LU-10271 hsm: don't release with wrong size

LU-10271 hsm: don't release with wrong size

The result of ll_merge_attr operation was ignored during
ll_hsm_release. For this case the released file could have
the wrong size on MDS, like
File: ‘released.file’
Size: 0  Blocks: 0  IO Block: 4194304 regular empty file

Patch adds test_253 sanity-hsm, to check hsm release
operation when cl_object_attr_get failed. It produces
the wrong size-on-mds for a released file.

Signed-off-by: Alexander Boyko <c17825@cray.com>
Change-Id: I94df1889265e5b6d03b16745de93e52af95d5b7c
Reviewed-on: https://review.whamcloud.com/30240
Reviewed-by: Henri Doreau <henri.doreau@cea.fr>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Sergey Cheremencev <c17829@cray.com>
Reviewed-by: Quentin Bouget <quentin.bouget@cea.fr>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>