release: ensure default sudo flavor is selected

[dch]

Summary

PR: 284278 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=284278

pkg behaviour now seems to select the non-default flavour, which means that cloudware
images just got ~ 500MiB bigger across the board (in CURRENT, using latest pkg repo,
others will be on quarterly, and not hit by this yet).

We should patch this in the interim, at least, until at least pkg behaviour is clarified.

[cperciva]

Please commit, thanks!