Always use absolute URLs for image diff review thumbnails

Review Request #8390 — Created Sept. 8, 2016 and submitted — Latest diff uploaded

Information

Review Board
release-2.5.x

Reviewers

Previously, only single image (or the latest image in a image diff) were
using absolute URLs in thumbnails, which would result in them not being
renderable in e-mails. This patch addresses the issue.

  • Ran unit tests.
  • Checked the generated HTML and saw that an absolute URL was used.