Finally worked out why a enumerate trusted domains was returning a

Finally worked out why a enumerate trusted domains was returning a
NT_STATUS_UNABLE_TO_FREE_VM error.  This error code was mis-defined
as 0x8000001a instead of 0xc000001a.  The former is actually a
NT_STATUS_NO_MORE_ENTRIES warning which is what we see in the status
code.

Removed the & 0xffffff from the loop in get_nt_error_msg() as all the
error constants now have the correct high bits set.