Fix restarting problems when changing both supervisord and managed services configs

Puppet fails to restart managed services when both supervisord.conf and configs of managed services has been changed simultaneously. This happens: `/etc/init.d/supervisor restart` and `supervisorctl restart <some_service>` happen simultaneously and  `supervisorctl restart <some_service>` can't connect to shutting down/still starting main processes with a message like 
```
Execution of '/usr/bin/supervisorctl start create_website:*' returned 2: error: <class 'xmlrpclib.Fault'>, <Fault 6: 'SHUTDOWN_STATE'>: file: /usr/lib/python2.6/xmlrpclib.py line: 838
```

The fix is to serialize this two services.
This also fixes #62