This is a merge of the NETLOGON schannel server code from Samba

This is a merge of the NETLOGON schannel server code from Samba
TNG. Actually, it exists in the main Samba cvs tree in APPLIANCE_TNG
as I found out later :-)

It adds a new parameter: server schannel = yes/auto/no defaulting to
auto.

What does this mean to the user: No requireSignOrSeal registry patch
for XP anymore.

Many thanks for this code to Luke Leighton, Elrond and anybody else I
forgot to mention.

My next thing will be to see if this applies cleanly to 3_0.

Please test and comment!

Volker