Change some string literals to be unicode, because:

    * It's the most micro of optimizations (forget I even said it)
    * It makes significantly more sense semantically, given these are functions which return unicode.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16957 bcc190cf-cafb-0310-a4f2-bffc1f526a37