ee-specific-lines-check should take the old base one commit before the one we want
This is discovered in https://gitlab.com/gitlab-org/gitlab-ee/issues/5912#note_72074990
It's pretty clearly explained in: https://content.pivotal.io/blog/git-rebase-onto
So instead of doing:
run_git_command("rebase --onto #{ce_merge_base} canonical-ce/master #{ce_fetch_head}")
We need to do:
old_base = run_git_command("merge-base canonical-ce/master #{ce_fetch_head}")
run_git_command("rebase --onto #{ce_merge_base} #{old_base}~1 #{ce_fetch_head}")