http NTLM: remaining bits from 0001-Moved-ntlm-[...]-curl_ntlm-mod_3.patch

* Added function comments:
    - Curl_ntlm_decode_type2_message
    - Curl_ntlm_create_type1_message
    - Curl_ntlm_create_type3_message

* Modification of ntlm processing state to NTLMSTATE_TYPE2 is now done
  only when Curl_ntlm_decode_type2_message() has fully succeeded.