Change some uses of cStringIO.StringIO to io.StringIO.
This is undoubtedly insufficient and in some cases just as broken as before.
diff --git a/Lib/xdrlib.py b/Lib/xdrlib.py
index 2f5db9b..055ee82 100644
--- a/Lib/xdrlib.py
+++ b/Lib/xdrlib.py
@@ -5,10 +5,7 @@
 """
 
 import struct
-try:
-    from cStringIO import StringIO as _StringIO
-except ImportError:
-    from StringIO import StringIO as _StringIO
+from io import StringIO as _StringIO
 
 __all__ = ["Error", "Packer", "Unpacker", "ConversionError"]