qemu: avoid dereferencing a NULL pointer
qemu: avoid dereferencing a NULL pointer

* src/qemu/qemu_process.c: Taking if (qemuDomainObjEndJob(driver, obj) == 0)
  true branch then 'obj' is NULL, virDomainObjIsActive(obj) and
  virDomainObjUnref(obj) will dereference NULL pointer.

Signed-off-by: Alex Jia <e236faec8cb8371bfb245ba3769a84afc9a11438@redhat.com>

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