illumos gate

Upstream of Joyent OS-7274.

Noticed during testing of OS-6576, the digest tests would sometimes crash during shutdown. Looking at the cores, they were crashing during C_DestroyOject. The crypto test PKCS#11 version of crypto_op_t structure contains a field for a handle to a key object. Unfortunately this is only initialized for the tests that use the key (i.e. the encryption tests), but not for the digest tests. This can cause a crash on deallocation if the value happens to contain something other than 0 (always an invalid handle value) due to OS-6601 (pkcs11softtoken should_ just fail with CKR_OBJECT_HANDLE_INVALID if given an invalid handle to destroy, but OS-6601 prevents that). Regardless, we should explicitly initialize the key object to CK_INVALID_HANDLE so we know if we've used it or not (and need to destroy it).