Revert removal of sidekiq log symlink

This reverts merge request !4173 (merged)

Without manage_symlink_source property, file resource will attempt to follow symlinks on actions. This means, !4173 (merged) caused omnibus-gitlab to attempt deletion of /var/log/gitlab/sidekiq/current. This caused errors in our production fleet where /var/log/sidekiq doesn't exist, at all (since Sidekiq runs separate).

Also, we only want to delete the symlink, not the file that it points to.