Fix verification list on do_clone()
requested to merge adalessandro/osc-plugin-clone:wip/adalessandro/fix-osc-fork-infinite-loop into master
Task https://phabricator.apertis.org/T8677
During the cloning process, all packages in the source project must be verified.
There's currently a bug in the do_clone() logic, where packages originally in the destination project are checked, instead of the source.
Because of the above reason, starting with an empty destination project will cause a infinite loop where no package is checked on each iteration. Fix this.