[1/2] Added a test: registering device interface and gettingdevicepath

[Juan Lang]

>  GetLastError() returns an unsigned value, and winerror.h lists error values
>  in decimal (if anyone really wants to match a trace with a symbolic name).

That's not strictly true.  The cryptoapi errors are defined as
HRESULTs , but are returned via GetLastError.  More relevant to this
patch is that the setupapi errors are defined as bitmasks, and are
also returned via GetLastError.

I picked %08x for a reason in this code--it's far easier to find the
relevant error using it than using %u.
--Juan