Fix byte concatenation in Python 3.4

This line worked in Python 3.5 because of PEP 461:

https://www.python.org/dev/peps/pep-0461/

but not in Python 3.4.

messytables/commas.py

@@ -74,7 +74,7 @@ def __init__(self, name, fileobj, delimiter=None, quotechar=None,
 
         # For line breaking, use the (detected) encoding of the file:
         linesep = [t.encode(self.encoding) for t in LINE_SEPARATOR]
-        linesep = b'(%s)' % b'|'.join(linesep)
+        linesep = b'(' + b'|'.join(linesep) + b')'
         self.linesep = re.compile(linesep)
 
         self._sample = []