Ensure self._uuid isn't None

(otherwise os.path.join will give an exception)

Author: alahiff

simvue/run.py

@@ -203,7 +203,10 @@ def _start(self, reconnect=False):
         """
         if self._mode == 'disabled':
             return True
-
+        
+        if self._mode != 'offline':
+            self._uuid = 'notused'
+            
         logger.debug('Starting run')
 
         self._check_token()