fix,bootstrap: Fix sed to change to permissive for short-name-mode

What this PR does / why we need it:

There was a recent change in how the containers-common rpm is built[1] which led to a slight formatting change to registries.conf.

This results in short-name-mode remaining in enforcing mode which breaks a number of jobs that still do not use full names for images[2]

[1] https://github.com/containers/common/commit/5c5b1120aaa2970d1b6c961ba2d48996fb240c6a [2] https://prow.ci.kubevirt.io/view/gs/kubevirt-prow/pr-logs/pull/kubevirt_kubevirtci/1209/check-provision-alpine-with-test-tooling/1812792004837380096#1:build-log.txt%3A792

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged): Fixes #

Special notes for your reviewer:

/cc @dhiller

Checklist

This checklist is not enforcing, but it's a reminder of items that could be relevant to every PR. Approvers are expected to review this list.

[ ] Design: A design document was considered and is present (link) or not required
[ ] PR: The PR description is expressive enough and will help future contributors
[ ] Code: Write code that humans can understand and Keep it simple
[ ] Refactor: You have left the code cleaner than you found it (Boy Scout Rule)
[ ] Upgrade: Impact of this change on upgrade flows was considered and addressed if required
[ ] Testing: New code requires new unit tests. New features and bug fixes require at least on e2e test
[ ] Documentation: A user-guide update was considered and is present (link) or not required. You want a user-guide update if it's a user facing feature / API change.
[ ] Community: Announcement to kubevirt-dev was considered

Release note:

kubevirt / project-infra

fix,bootstrap: Fix sed to change to permissive for short-name-mode #3529