Suppose you're running with --dur, that you then have an unclean shutdown. If you manage to start a mongod and forget --dur, the mongod exits with the old message about removing the lock file and running repair. Ideally we shouldn't tell people to run repair if they've got a journal, but should instead tell them to run with --dur, as we do if they start up without --dur and the journal exists but the lock file doesn't.