LU-10399 test: use /dev/urandom in sanity-hsm test_1b()

LU-10399 test: use /dev/urandom in sanity-hsm test_1b()

In sanity-hsm test_1b() use /dev/urandom instead of /dev/random so we
won't have to wait for the second law of thermodynamics to become
true.

Test-Parameters: trivial testlist=sanity-hsm
Lustre-change: https://review.whamcloud.com/30556
Lustre-commit: 54cf0962e286b8f1bcfca490cf828fd126f1fa60

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: Ib64691fd6ee1a172c631ffa55956e1d69f24d349
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Reviewed-by: Quentin Bouget <quentin.bouget@cea.fr>
Signed-off-by: Minh Diep <minh.diep@intel.com>
Reviewed-on: https://review.whamcloud.com/30722
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>