The PKCS#11 backend key-wraps (encrypts) the project-specific Key
Encryption Keys (pKEKs) using the master encryption key (MKEK).
The mechanism for wrapping/unwrapping the keys was hard-coded to use
CKM_AES_CBC_PAD. This patch refactors the pkcs11 module to make this
mechanism configurable.
This is necessary to fix Bug #2036506 because some PKCS#11 devices and
software implementations no longer allow CKM_AES_CBC_PAD to be used for
key wrapping.
Supported key wrap mechanisms now include:
* CKM_AES_CBC_PAD
* CKM_AES_KEY_WRAP_PAD
* CKM_AES_KEY_WRAP_KWP
Closes-Bug: #2036506
Change-Id: Ic2009a2a55622bb707e884d6a960c044b2248f52
0d4101fa5d