Locked scripts do not report lock file location

Sometimes it's necessary to kill off scripts. Sad but true. When this happens, sometimes they leave their lock file around. This means that such scripts cannot re-launch.

Naturally, the thing to do is to delete the lock file, indicating that it was killed off deliberately. However, it's actually rather difficult to find where this might be. The message, e.g., "Another instance of add_import_jobs is already running", doesn't give you any clues.

Ideally, when something is locked, it tells you where it's locked, or at least gives you a pointer to some way that you can figure it out.