Use XPath when parsing snapshot disk definition
Use XPath when parsing snapshot disk definition

Instead of going through XML nodes in a loop and
having to check if they are duplicate.

VenkatDatta/libvirt,crobinso/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,rlaager/libvirt,taget/libvirt,olafhering/libvirt,nertpinx/libvirt,nertpinx/libvirt,jardasgit/libvirt,eskultety/libvirt,datto/libvirt,fabianfreyer/libvirt,datto/libvirt,rlaager/libvirt,libvirt/libvirt,jfehlig/libvirt,olafhering/libvirt,fabianfreyer/libvirt,zippy2/libvirt,crobinso/libvirt,andreabolognani/libvirt,VenkatDatta/libvirt,libvirt/libvirt,agx/libvirt,libvirt/libvirt,olafhering/libvirt,agx/libvirt,VenkatDatta/libvirt,taget/libvirt,andreabolognani/libvirt,andreabolognani/libvirt,datto/libvirt,datto/libvirt,zippy2/libvirt,rlaager/libvirt,agx/libvirt,taget/libvirt,agx/libvirt,olafhering/libvirt,crobinso/libvirt,eskultety/libvirt,VenkatDatta/libvirt,eskultety/libvirt,jfehlig/libvirt,rlaager/libvirt,datto/libvirt,agx/libvirt,jardasgit/libvirt,fabianfreyer/libvirt,zippy2/libvirt,eskultety/libvirt,taget/libvirt,VenkatDatta/libvirt,nertpinx/libvirt,jardasgit/libvirt,jardasgit/libvirt,rlaager/libvirt,nertpinx/libvirt,crobinso/libvirt,libvirt/libvirt,zippy2/libvirt,jardasgit/libvirt,eskultety/libvirt,taget/libvirt,jfehlig/libvirt,jfehlig/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt