Fixed an ancient clone-find-all bug: under some circumstance cloned nodes retained their clone mark after the penultimate clone was deleted.
Reloading the .leo file corrects this problem, which may be why nobody noticed it until now.
This bug has been around for a long time, possibly the date of a now-unused import: 2014/04/24. It has nothing to do with recent work.

To see this bug in action:
- clone-find-all-flattened of "v.fileIndex ="
- deleted a node.

The node still has a clone mark and still has the "Found v.fileIndex =" node in v.parents!!

Leo build: 20141023114930