L2SS-777: fix bugs in devices function

docker-compose/tango-prometheus-exporter/code/tango-prometheus-client.py

@@ -69,9 +69,9 @@ class ArchiverPolicy(object):
         # Devices listed in policy file
         config_devices = list(k.lower() for k in self.config["devices"].keys())
         # Multimember device list
-        multimember_devices = self.multimember_device_list
+        multimember_devices = self.multimember_device_list(config_devices)
         # Filter devices following policy file
-        devices = [x for x in db_devices if x in config_devices]
+        devices = list( set(db_devices) & set(config_devices) ) # list intersection
         devices += multimember_devices
         return devices