code: func (x *Index) isDeletedNoCache(br blob.Ref) bool {
  	var err error
  	it := x.queryPrefix(keyDeleted, br)
  	for it.Next() {
  		cl, ok := kvDeleted(it.Key())
  		if !ok {
  			panic(fmt.Sprintf("Bogus keyDeleted entry key: want |\"deleted\"|<deleted blobref>|<reverse claimdate>|<deleter claim>|, got %q", it.Key()))
  		}
  		if !x.isDeletedNoCache(cl.BlobRef) {
  			closeIterator(it, &err)
  			if err != nil {
  				// TODO: Do better?
  				panic(fmt.Sprintf("Could not close iterator on keyDeleted: %v", err))
  			}
  			return true
  		}
  	}
  	closeIterator(it, &err)
  	if err != nil {
  		// TODO: Do better?
  		panic(fmt.Sprintf("Could not close iterator on keyDeleted: %v", err))
  	}
  	return false
  }
docs: // Used when the Index has no deletes cache (x.deletes is nil).