partition_version: Make is_referenced() const-qualified
partition_version: Make is_referenced() const-qualified

avikivity/scylla,scylladb/scylla,duarten/scylla,scylladb/scylla,duarten/scylla,duarten/scylla,scylladb/scylla,scylladb/scylla,avikivity/scylla,avikivity/scylla