ntlm: improve code style and readability

ntlm: improve code style and readability

This patch does not introduce any functional or behavioural change.

The code in ntlm.c has been restyled to better to obey to the
new coding style and its readability has been a improved a bit.

Signed-off-by: Antonio Quartulli <a@unstable.cc>
Acked-by: Steffan Karger <steffan@karger.me>
Message-Id: <20170710043441.24770-5-a@unstable.cc>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg15028.html
Signed-off-by: David Sommerseth <davids@openvpn.net>
(cherry picked from commit c310f1ecba905f091e3a31cb3e6cba5ae75e996b)