This commit includes part of the patch from metze posted to the list, and a few

This commit includes part of the patch from metze posted to the list, and a few
of my own changes.

In particular:  I've added a SAM_ASSERT macro.  This expands to either
SMB_ASSERT() (which should help us track down bugs) or a return of
NT_STATUS_CHECK_FAIL.

Metze's changes are mostly to bring the code into line with current discussions
on things like adding users/groups, flags etc.

I've adjusted a fair bit of the 'const' in the SAM stuff.  Const is currently
used only for pointers, not for local variables or non-pointer paramters.  The
benifits and reasons for extending this further need discussion on
samba-technical.

Also, some of the 'context' paramters should not be const, to allow backend
modules to do fancy caching etc in them.

Andrew Bartlett
(This used to be commit e13bc432628a6131be082caedc75cd8a3d206e5a)