vcard-manager.c: use node iteration wrappers
vcard-manager.c: use node iteration wrappers

mlundblad/telepathy-gabble,mlundblad/telepathy-gabble,jku/telepathy-gabble,Ziemin/telepathy-gabble,community-ssu/telepathy-gabble,community-ssu/telepathy-gabble,community-ssu/telepathy-gabble,jku/telepathy-gabble,Ziemin/telepathy-gabble,Ziemin/telepathy-gabble,jku/telepathy-gabble,Ziemin/telepathy-gabble,mlundblad/telepathy-gabble,community-ssu/telepathy-gabble