[RFC] Drop --enable-ntlm-fail-open

[Amos Jeffries]

While building the helper changes it has become clear that the 
--enable-ntlm-fail-open feature has been half missing for quite some time.
The SMB helper sends the LD code back to Squid when the directive is 
compiled in, but there is no Squid code handling such responses, back as 
far as squid-2.

Given that in all the time this appears to be broken we have only had 
one complaint, form someone who was only experimenting with NTLM 
options. I think its overdue for complete removal.

Amos