Fix 2 bugs in 'undo' implementation

- make 'undo' compatible with ZODB 3.9.x
- fix load of original version of object

git-svn-id: https://svn.erp5.org/repos/neo/trunk@2765 71dcc9de-d417-0410-9af5-da40c76e7ee4

neo/client/app.py

@@ -860,9 +860,9 @@ class Application(object):
                 # object. This is an undo conflict, try to resolve it.
                 try:
                     # Load the latest version we are supposed to see
-                    data = self.load(oid, current_serial, snapshot_tid)[0]
+                    data = self.load(oid, current_serial)[0]
                     # Load the version we were undoing to
-                    undo_data = self.load(oid, undo_serial, snapshot_tid)[0]
+                    undo_data = self.load(oid, undo_serial)[0]
                 except NEOStorageNotFoundError:
                     raise UndoError('Object not found while resolving undo '
                         'conflict')
@@ -878,6 +878,8 @@ class Application(object):
                 undo_serial = None
             self._store(txn_context, oid, current_serial, data, undo_serial)
 
+        return None, () # required for ZODB < 3.10
+
     def _insertMetadata(self, txn_info, extension):
         for k, v in loads(extension).items():
             txn_info[k] = v