Added close to avoid a tear-down failure on Windows.

src/ZEO/tests/test_cache.py

@@ -297,6 +297,8 @@ __test__ = dict(
     ...     loaded = cache.load(ZODB.utils.p64(oid))
     ...     if loaded != expected:
     ...         print oid, loaded
+
+    >>> cache.close()
     
     """,
     )