Add open() no-op method to zodb base test case.

This method is the symetric of close() on Storage (see previous commit) and
is required for some ZODB tests. Support read_only attribute.

git-svn-id: https://svn.erp5.org/repos/neo/trunk@1794 71dcc9de-d417-0410-9af5-da40c76e7ee4

neo/tests/zodb/__init__.py

@@ -38,3 +38,7 @@ class ZODBTestCase(NEOFunctionalTest):
         self._storage.cleanup()
         self.neo.stop()
 
+    def open(self, read_only=False):
+        # required for some tests (see PersitentTests), no-op for NEO ?
+        self._storage._is_read_only = read_only
+