Off by 1 error in the commit history view vs the actual blob view

Created by: alexfogg

• Sourcegraph version: Sourcegraph.com

Steps to reproduce:

1. See original deleted file. It has 16 lines.
2. See deletion. Shows 16 lines deleted.
3. Click Deleted files aren't rendered by default. Click here to view.

Expected behavior:

It should say 16 lines deleted and the diff should show 16 deleted lines.

Actual behavior:

The last line is missing. It says 16 lines deleted but only shows 15 deleted lines.