Diffs Never Load for Deleted Files that Have More than 10,000 Lines

If a file has greater than 10,000 lines and is then deleted the diff will never load on a pull request.

This can be reproduced by:

1. Creating a file with 10,001 lines
2. Adding that file and committing it to a branch (add)
3. Creating a new branch from the original named remove
4. Deleting that file, committing and pushing both branches
5. Creating a pull request with a source of remove and destination of add
6. Viewing the diff tab of the pull request will cause the request to spin because of a JS error:

JS console shows a Uncaught TypeError: Cannot read property 'toString' of null on line 2505 of batch.js

File type does not seem to be of consequence this works on several versions of Stash.

Changing page.max.diff.lines=10000 in stash-config.properties has no effect either.