LU-9183 llite: handle make the string hashes salt the hash

LU-9183 llite: handle make the string hashes salt the hash

In commit 8387ff2577eb9ed245df9a39947f66976c6bcd02 Linus Torvalds
make the string hashes salt the hash.

Hash users that don't have any particular initial salt can just use
the NULL pointer as a no-salt.

Change-Id: Id262d459370aa46c2e3d0e8b1e09dad74c717f03
Signed-off-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-on: https://review.whamcloud.com/25819
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>