Run post-commit SVN diffs through convert_to_unicode.

Review Request #6763 — Created Jan. 12, 2015 and submitted — Latest diff uploaded

Information

Review Board
release-2.0.x
3af12e5...

Reviewers

We were blindly interpreting the results of the lower-level SVN libraries' diff
commands as utf-8. This worked until now, but it failed for a certain
iso-8859-1 character. This change switches us to use our fancy
convert_to_unicode method, which will try utf-8, anything that's configured for
the repository, and iso-8859-1.

Ran unit tests.