r1004: continue tridge's work on dcerpc server auth/crypto code

r1004: continue tridge's work on dcerpc server auth/crypto code
I made it much more generic, and we should be able to add a
module interface to this code, so that other DCERPC_AUTH types can be added
via modules...

metze
(This used to be commit d09abeb686c43c62322205689273d1b417113004)