Fix unicode errors with utf-8 files that have svn:keywords set.
Review Request #6052 — Created July 3, 2014 and submitted
In the case where a file in SVN had both unicode characters in it and
svn:keywords, trying to fetch the files would cause UnicodeDecodeErrors when
processing the keywords. I've fixed things up to do all the regex work in bytes
mode.
Ran unit tests. Before the changes to svn/base.py, the new test failed with the
same error as in the bug reports we've received about this. After, the test
runs fine.