signature.
Use secondary key to calculate signature in case of ntlmssp.

For ntlmv2 within ntlmssp, during signature calculation, only 16 bytes key
(a nonce) stored within session key is used. during smb signature calculation.
For ntlm and ntlmv2 without extended security, 16 bytes key
as well as entire response (24 bytes in case of ntlm and variable length
in case of ntlmv2) is used for smb signature calculation.
For kerberos, there is no distinction between key and response.

Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>