Be a bit more defensive about cache contents

src/Products/StandardCacheManagers/AcceleratedHTTPCacheManager.py

@@ -174,6 +174,8 @@ class AcceleratedHTTPCacheManager (CacheManager, SimpleItem):
 
     security.declarePrivate('_remove_data')
     def _remove_data(self):
+        cid = self.__cacheid
+        if cid in caches:
             caches.pop(self.__cacheid)
 
     security.declarePrivate('_resetCacheId')