you might want to look at /usr/sbin as the scripts could be there, I do not recall exactly. If I am not mistaken they will be planeshift, planeshift-updater and planeshift-settings. It does kind of depend on what type of install you did. I suppose you could try to run one of those in your terminal. You will either get a file not found message or proof that you need to delete them from wherever they might be.