Now that cekit 3.0.0 (via dnf) and 3.0.1 (via pip) have been released, the --sha512 flag is now supported, so it can be added to the cekit-cache command in build-overrides.sh.

Also, build-osbs.sh should have the ability to pass a --no-color flag to build-overrides.sh, as otherwise terminal color codes show up in the jenkins build logs.