Modified script to not use PS 3.0 constructs

Change-Id: I0a4a738a410f0aece9459852a51d6c96f11aae76
Reviewed-on: https://code.wireshark.org/review/3739
Reviewed-by: Graham Bloice <graham.bloice@trihedral.com>
Petri-Dish: Graham Bloice <graham.bloice@trihedral.com>
Reviewed-by: Pascal Quantin <pascal.quantin@gmail.com>
Reviewed-by: Anders Broman <a.broman58@gmail.com>