snapshot: use qemu-img on disks in use at time of snapshot
snapshot: use qemu-img on disks in use at time of snapshot

Once we know which set of disks belong to a snapshot, reverting or
deleting that snapshot should visit just those disks, rather than
also visiting disks that were hot-plugged in the meantime or
skipping disks that were hot-unplugged in the meantime.

* src/qemu/qemu_domain.c (qemuDomainSnapshotForEachQcow2): Use
snapshot domain details when available.  Avoid NULL deref.

zhlcindy/libvirt-1.1.4-maintain,elmarco/libvirt,cbosdo/libvirt,datto/libvirt,novel/fbsd-libvirt,emaste/libvirt,jardasgit/libvirt,rmarwaha/libvirt1,dumbbell/libvirt,rmarwaha/libvirt1,dumbbell/libvirt,jeckersb/libvirt,rmarwaha/libvirt1,iam-TJ/libvirt,jeckersb/libvirt,novel/fbsd-libvirt,bjzhang/libvirt,rlaager/libvirt,soulxu/libvirt-xuhj,VenkatDatta/libvirt,foomango/libvirt,agx/libvirt,bjzhang/libvirt,nertpinx/libvirt,datto/libvirt,libvirt/libvirt,iam-TJ/libvirt,zhlcindy/libvirt-1.1.4-maintain,cbosdo/libvirt,cbosdo/libvirt,dumbbell/libvirt,emaste/libvirt,iam-TJ/libvirt,wiedi/libvirt,VenkatDatta/libvirt,VenkatDatta/libvirt,rmarwaha/libvirt1,rmarwaha/libvirt1,dumbbell/libvirt,olafhering/libvirt,wiedi/libvirt,dumbbell/libvirt,shugaoye/libvirt,libvirt/libvirt,jardasgit/libvirt,olafhering/libvirt,nertpinx/libvirt,warewolf/libvirt,jeckersb/libvirt,iam-TJ/libvirt,bjzhang/libvirt,bjzhang/libvirt,novel/fbsd-libvirt,rlaager/libvirt,warewolf/libvirt,agx/libvirt,rmarwaha/libvirt1,trainstack/libvirt,foomango/libvirt,taget/libvirt,usc-isi/libvirt,siboulet/libvirt-openvz,leilihh/libvirt,agx/libvirt,soulxu/libvirt-xuhj,VenkatDatta/libvirt,soulxu/libvirt-xuhj,rmarwaha/libvirt,crobinso/libvirt,agx/libvirt,fabianfreyer/libvirt,trainstack/libvirt,warewolf/libvirt,fabianfreyer/libvirt,cbosdo/libvirt,taget/libvirt,jfehlig/libvirt,cbosdo/libvirt,andreabolognani/libvirt,zippy2/libvirt,wiedi/libvirt,novel/fbsd-libvirt,emaste/libvirt,shugaoye/libvirt,jeckersb/libvirt,zippy2/libvirt,nertpinx/libvirt,taget/libvirt,eskultety/libvirt,shugaoye/libvirt,andreabolognani/libvirt,zippy2/libvirt,trainstack/libvirt,elmarco/libvirt,novel/fbsd-libvirt,jfehlig/libvirt,novel/fbsd-libvirt,zhlcindy/libvirt-1.1.4-maintain,zhlcindy/libvirt-1.1.4-maintain,emaste/libvirt,bjzhang/libvirt,datto/libvirt,novel/fbsd-libvirt,eskultety/libvirt,taget/libvirt,emaste/libvirt,foomango/libvirt,fabianfreyer/libvirt,danwent/libvirt-ovs,novel/fbsd-libvirt,iam-TJ/libvirt,soulxu/libvirt-xuhj,jeckersb/libvirt,novel/fbsd-libvirt,dumbbell/libvirt,eskultety/libvirt,shugaoye/libvirt,elmarco/libvirt,warewolf/libvirt,leilihh/libvirt,danwent/libvirt-ovs,leilihh/libvirt,nertpinx/libvirt,eskultety/libvirt,fabianfreyer/libvirt,warewolf/libvirt,rmarwaha/libvirt,shugaoye/libvirt,andreabolognani/libvirt,wiedi/libvirt,agx/libvirt,wiedi/libvirt,danwent/libvirt-ovs,danwent/libvirt-ovs,trainstack/libvirt,leilihh/libvirt,rlaager/libvirt,datto/libvirt,eskultety/libvirt,usc-isi/libvirt,olafhering/libvirt,elmarco/libvirt,wiedi/libvirt,datto/libvirt,iam-TJ/libvirt,taget/libvirt,trainstack/libvirt,jardasgit/libvirt,jfehlig/libvirt,jeckersb/libvirt,rmarwaha/libvirt,rmarwaha/libvirt,jfehlig/libvirt,emaste/libvirt,soulxu/libvirt-xuhj,warewolf/libvirt,usc-isi/libvirt,leilihh/libvirt,siboulet/libvirt-openvz,rmarwaha/libvirt,rlaager/libvirt,VenkatDatta/libvirt,libvirt/libvirt,trainstack/libvirt,jeckersb/libvirt,andreabolognani/libvirt,usc-isi/libvirt,usc-isi/libvirt,wiedi/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,andreabolognani/libvirt,siboulet/libvirt-openvz,foomango/libvirt,crobinso/libvirt,iam-TJ/libvirt,danwent/libvirt-ovs,trainstack/libvirt,siboulet/libvirt-openvz,nertpinx/libvirt,crobinso/libvirt,warewolf/libvirt,rlaager/libvirt,jardasgit/libvirt,leilihh/libvirt,crobinso/libvirt,zippy2/libvirt,libvirt/libvirt,olafhering/libvirt,siboulet/libvirt-openvz,elmarco/libvirt,foomango/libvirt,zhlcindy/libvirt-1.1.4-maintain,rmarwaha/libvirt,emaste/libvirt