Uses 127.0.0.1 for calendar server.

tracim/tracim/config/app_cfg.py

 
         self.RADICALE_SERVER_HOST = tg.config.get(
             'radicale.server.host',
-            '0.0.0.0',
+            '127.0.0.1',
         )
         self.RADICALE_SERVER_PORT = int(tg.config.get(
             'radicale.server.port',