Introduced the parameter 'hmac_keywrap_mechanism' in group
'[p11_crypto_plugin]' in Barbican config. The default value, which were
hard coded before, is 'CKM_SHA256_HMAC'. This defines the machanism used
to compute the HMAC from an wrapped PKEK. However with Utimaco HSMs this
leads to an CKR_MECHANISM_INVALID error. Therefore for Utimaco HSMs
'hmac_keywrap_mechanism' has to be changed to 'CKM_AES_MAC'.
Change-Id: I53537a96bc4b2acb30be5fa85e10bac89917851f
Story: 2004833
Task: 29027
b7da1f771c