DocCollection object's hashcode/equals method should consider prs state

// code placeholder
@Override
public boolean equals(Object that) {
  if (!(that instanceof DocCollection)) return false;
  DocCollection other = (DocCollection) that;
  return super.equals(that)
      && Objects.equals(this.name, other.name)
      && this.znodeVersion == other.znodeVersion;
}

@Override
public int hashCode() {
  return Objects.hash(name, znodeVersion);
}