When tasks in db are renamed, the old task stays in scheduler and still runs on same predecessor

[jeffshumphreys]

Might even cause downstream stuff to trigger twice since they now are predecessors of the same task!

Example was 1) extract_genres_from_directories and 2) extract_genres_from_file_directories. Ugh.

Solution 1: Delete all tasks in scheduler first, per run set/folder.
Solution 2:Just delete ones not in database. Maybe keep old name, and mark delete? So as to find?