vz: make error path code idiomatic
vz: make error path code idiomatic

Signed-off-by: Nikolay Shirokovskiy <7fa0e2698a05be944b362bdf5d7736c0162e16c9@virtuozzo.com>
Signed-off-by: Maxim Nestratov <3521c777060d1ad4ae08bba7eb9d80264eaeb236@virtuozzo.com>

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