public1-a-codfw - also use install2001 not carbon

public1-a-codfw is just like the other codfw networks,
right? so then it would also use install2001, not carbon

follow-up to Change-Id: I27d7455364b1566bcec

Change-Id: Ia3e36cb60d8d609fbffa999ae0d0085b05cfeb34
Merge "public1-a-codfw - also use install2001 not carbon" into production