qemu: snapshot: Refactor image labelling of new snapshot files
qemu: snapshot: Refactor image labelling of new snapshot files

Now that cgroups/security driver/locking driver support labelling of
individual images and tolerate network storage we don't have to refrain
from passing all image files to it. This allows removing the checking
code as we already make sure that the snapshot function won't be called
with unsupported options.

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