[OE-core] [PATCH 1/5] cve-check: honor RM_OLD_IMAGE flag

[Marko, Peter]

> +                if d.getVar('RM_OLD_IMAGE') == "1":
> +                    os.remove(os.path.realpath(manifest_link))

I have been working with Krogoth and ported my changes to master.
It seems this flag is no longer supported, thus this commit is wrong (or good only for backporting to Krogoth).
I'll remove it in v2 as soon as I get feedback on the other commits, too.

Peter