SOFTHSM-83: Support CKA_VALUE_BITS for CKK_DH private key object
SOFTHSM-83: Update the NEWS
SOFTHSM-83: Initialize the value to zero.
Merge pull request #60 from bellgrim/SOFTHSM-83

SOFTHSM-83: Support CKA_VALUE_BITS for CKK_DH private key object