virPCIDeviceGetVPD: Fix multiple error handling bugs

virPCIDeviceGetVPD: Fix multiple error handling bugs

- fix passing of 'errno' to 'virReportSystemError'

 The 'open' syscall returns '-1' and sets 'errno' on failure. The code
 passed '-fd' as 'errno' rather than errno itself, thus always reporting
 EPERM.

- don't overwrite errors when closing FD

 Use VIR_AUTOCLOSE to avoid overwriting the errors from virPCIVPDParse.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>