LU-15921 tests: fix sanity-hsm 24c

LU-15921 tests: fix sanity-hsm 24c

Fix bad copy-paste in test sanity-hsm 24c causing
the test to save 3 different tunables, but actually
restoring the same one three times.

Also improve the code to support values including spaces.

Test-Parameters: trivial testlist=sanity-hsm,sanity-pcc
Fixes: 2042bce ("LU-9474 tests: rewrite copytool_setup to use stack_trap")
Fixes: f172b11 ("LU-10092 llite: Add persistent cache on client")
Change-Id: I34cc61515ebb862d5996f41cdb2055ac53ccac65
Signed-off-by: Aurelien Degremont <degremoa@amazon.com>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/47564
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Li Xi <lixi@ddn.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>