Report the user as member of the admins group.

Based on a patch by Dmitry Timoshkov.

All this does so far is create a handle and store the credential type in there.

This isn't the prettiest way to merge those functions, but it's a start.

This gives a small performance improvement for applications that are
smart enough to set the D3DPRESENTFLAG_DISCARD_DEPTHSTENCIL flag, or
to create depth stencils with Discard set to TRUE.