[MERGE] selftest fails if the committer name contains non-ASCII characters

[Aaron Bentley]

Aaron Bentley has voted tweak.
Status is now: Conditionally approved
Comment:
It looks like make_utf8_encoded_stringio uses StringIOWrapper for no 
reason, since codecs.getwriter wraps it.  Other than that, looks okay.

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C1186586988.6203.23.camel%40nemo%3E