[Libvir] PATCH: Don't send callbacks invalid credentials

The PolicyKit auth code was invoking the authentication callback even if the app hadn't indicated support for VIR_CREDENTIAL_EXTERNAL. The default authentication callback was also not returning errors for credentials it doesn't support. This patch fixes both those flaws Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|