[#1445] local_object_storage: Append expiration epoch to graves

In the near future the garbage collector will delete expired tombstones
and graves separately. So, all graves should have expiration epochs.

Signed-off-by: Aleksey Savchuk <a.savchuk@yadro.com>

scripts/populate-metabase/internal/populate.go

@@ -186,6 +186,7 @@ func PopulateGraveyard(
 			prm := meta.InhumePrm{}
 			prm.SetAddresses(addr)
 			prm.SetTombstoneAddress(tsAddr)
+			prm.SetTombstoneExpEpoch(rand.Uint64())
 
 			group.Go(func() error {
 				if _, err := db.Inhume(ctx, prm); err != nil {