Fix diff headers in e-mails.
Review Request #3368 — Created Sept. 28, 2012 and submitted
Fix diff headers in e-mails. The e-mails weren't updated for the new diff header data, causing the e-mails to show json blocks instead of header text. We now use the same logic that we use in the diff renderer template.
Tested the preview-email URL for a review. Saw the correct headers.