ntlm authentication and signing - Correct response length for ntlmv2 authentication without extended security

Fix incorrect calculation of case sensitive response length in the
ntlmv2 (without extended security) response.
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>