Fixed the choice include tests.

--HG--
branch : trunk
diff --git a/jinja2/exceptions.py b/jinja2/exceptions.py
index 96194a9..acb26db 100644
--- a/jinja2/exceptions.py
+++ b/jinja2/exceptions.py
@@ -59,7 +59,7 @@
     def __init__(self, names=(), message=None):
         if message is None:
             message = u'non of the templates given were found: ' + \
-                      u', '.join(names)
+                      u', '.join(map(unicode, names))
         TemplateNotFound.__init__(self, names and names[-1] or None, message)
         self.templates = list(names)