Made MappingStorage a new-style class.

src/ZODB/MappingStorage.py

@@ -27,7 +27,7 @@ import ZODB.TimeStamp
 import ZODB.utils
 import zope.interface
 
-class MappingStorage:
+class MappingStorage(object):
     
     zope.interface.implements(
         ZODB.interfaces.IStorage,

src/ZODB/tests/blob_connection.txt

@@ -94,7 +94,7 @@ You can't put blobs into a database that has uses a Non-Blob-Storage, though:
     >>> transaction2.commit()        # doctest: +ELLIPSIS
     Traceback (most recent call last):
         ...
-    Unsupported: Storing Blobs in <ZODB.MappingStorage.MappingStorage instance at ...> is not supported.
+    Unsupported: Storing Blobs in <ZODB.MappingStorage.MappingStorage object at ...> is not supported.
 
     >>> transaction2.abort()
     >>> connection2.close()