Multifile.read():  Fix a broken conversion to string methods.

This closes SF bug #407777.
diff --git a/Lib/multifile.py b/Lib/multifile.py
index 60a4303..c3c468a 100644
--- a/Lib/multifile.py
+++ b/Lib/multifile.py
@@ -117,7 +117,7 @@
         return list
 
     def read(self): # Note: no size argument -- read until EOF only!
-        return self.readlines().join('')
+        return ''.join(self.readlines())
 
     def next(self):
         while self.readline(): pass