None in nodelist caused an issue - fixed

Author: OutlyingWest

src/jumper/perfdatahandler.py

@@ -70,7 +70,7 @@ def set_monitor(self, monitor):
             self.nodelist = None
 
     def get_nodelist(self):
-        return self.nodelist
+        return self.nodelist if self.nodelist else []
 
     def get_perfdata_history(self):
         return self.performance_data_history