Fix crash on bad MQTT config

blinky.py

@@ -28,7 +28,7 @@ def file_thread(file):
         def process_IN_CLOSE_WRITE(self, event):
             global reload, config
             with lock_reload:
-                print("Triggering reload")
+                print("Triggering file reload")
                 config = None
                 reload = True
                 cond_reload.notify_all()
@@ -54,9 +54,13 @@ def mqtt_thread():
     def on_message(client, userdata, message):
         global reload, config
         with lock_reload:
-            config = json.loads(message.payload)
-            reload = True
-            cond_reload.notify_all()
+            print("Triggering MQTT reload")
+            try:
+                config = json.loads(message.payload)
+                reload = True
+                cond_reload.notify_all()
+            except:
+                print("Invalid MQTT config")
 
     subscribe.callback(on_message, mqtt.topic, hostname=mqtt.hostname, auth=mqtt.auth, port=8883, tls=mqtt.tls)