Based orginally by work by Kai, this patch moves our NT_TOKEN generation into

Based orginally by work by Kai, this patch moves our NT_TOKEN generation into
our authenticaion code - removing some of the duplication from the current
code.

This also gets us *much* closer to supporting a real SAM backend, becouse the
SAM can give us the right info then.

This also changes our service.c code, so that we do a VUID (rather than uid)
cache on the connection struct, and do full NT ACL/NT_TOKEN checks (or cached
equivilant) on every packet, for the same r or rw mode the whole share was open
for.

Andrew Bartlett
(This used to be commit d8122cee059fc7098bfa7e42e638a9958b3ac902)