bundles/mosquitto: only install telegraf plugin if we have telegraf

bundles/mosquitto/metadata.py

@@ -5,7 +5,6 @@ defaults = {
         'packages': {
             'mosquitto': {},
             'mosquitto-clients': {},
-            'python3-paho-mqtt': {}, # for telegraf plugin
         },
     },
     'icinga2_api': {
@@ -24,6 +23,9 @@ defaults = {
     },
 }
 
+if node.has_bundle('telegraf'):
+    defaults['apt']['packages']['python3-paho-mqtt'] = {}
+
 
 @metadata_reactor.provides(
     'firewall/port_rules',