Some servers may not announce the NTLMSSP_NEGOTIATE_NTLM2
(a.k.a. NTLMSSP_NEGOTIATE_EXTENDED_SESSIONSECURITY) bit.

But if we're acting as a client using NTLMv2 we need to
enforce this flag, because it's not really a negotiationable
in that case.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=12862



Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
(cherry picked from commit 8ee4f823)

Autobuild-User(v4-5-test): Karolin Seeger <kseeger@samba.org>
Autobuild-Date(v4-5-test): Wed Jun 28 15:32:51 CEST 2017 on sn-devel-144