storage/index: add support for finding old/empty index objects
storage/index: add support for finding old/empty index objects

quantum/coreos-mantle,quantum/coreos-mantle,glevand/coreos--mantle,dm0-/mantle,mjg59/mantle,mjg59/mantle,glevand/coreos--mantle,dm0-/mantle,marineam/mantle,marineam/mantle