try: prevent supervisord from spamming stderr with python deprecation warnings

Author: mgmeier

nix/workbench/backend/supervisor-conf.nix

@@ -63,6 +63,7 @@ let
         logfile = "${stateDir}/supervisor/supervisord.log";
         pidfile = "${stateDir}/supervisor/supervisord.pid";
         strip_ansi = true;
+        loglevel = "error";
       };
       ##
       ## [supervisorctl] Section Settings