qemuDomainSnapshotCreateXML: avoid NULL dereferences
qemuDomainSnapshotCreateXML: avoid NULL dereferences

* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateXML): When setting
"vm" to NULL, jump over vm-dereferencing code to "cleanup".
(qemuDomainRevertToSnapshot): Likewise.

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