Fix un-escaped form fields for file and diff upload

Review Request #6853 — Created Jan. 31, 2015 and submitted — Latest diff uploaded

Information

Djblets
release-0.8.x
fc2b5a3...

Reviewers

Adding files to review requests didn't work for Italian (on Review Board version 2.0.8) because of an unescaped apostrophe. This fix makes sure form fields for file and diff upload are escaped.

Manual testing: set browser (Firefox 33) language to Italian, attached a file to a review request.