fix playground

- fix initialization
- add description

Change-Id: Ic210c26edfec709bafa902e32eae04350d571acd
Reviewed-on: https://forge.frm2.tum.de/review/c/secop/frappy/+/34874
Reviewed-by: Alexander Zaft <a.zaft@fz-juelich.de>
Reviewed-by: Georg Brandl <g.brandl@fz-juelich.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>

frappy/playground.py

@@ -97,7 +97,9 @@ class Playground(Server):
         for modname, cfg in kwds.items():
             cfg.setdefault('description', modname)
         self.log = logger.log
-        self.node_cfg = {'cls': 'frappy.playground.Dispatcher', 'name': 'playground'}
+        self.node_cfg = {'cls': 'frappy.playground.Dispatcher',
+                         'name': 'playground',
+                         'description': 'playground'}
         self._testonly = True  # stops before calling startModule
         self._cfgfiles = 'main'
         self.module_cfg = {}