User should not have called or deferred the Close() method should
SetupDiGetClassDevsEx() return an error (and invalid handle). And even
if user does that, a SetupDiDestroyDeviceInfoList(INVALID_HANDLE_VALUE)
is harmless. It just returns ERROR_INVALID_HANDLE - we have a unit test
for this in TestSetupDiDestroyDeviceInfoList().
Signed-off-by: Simon Rozman <simon@rozman.si>