release: Pass ABI to running pkgbase-stage on dvd

I did this for disc1 but forgot to amend the dvd invocation.

Fixes: 340e68fd7c0d ("release: Pass ABI to pkgbase-stage.lua")
MFC after: 3 days
Sponsored by: https://www.patreon.com/cperciva

(cherry picked from commit b050bfa88d4ee2acedb590777603e5c3656cdaca)