Applies workaround to get umask to apply correctly in Upstart.

Without this adjustment, you'll receive errors like these when you start the service. With this patch, the errors go away, and the services start. This is a workaround which introduces a different style of argument. I've opened [BZ 1118804](https://bugzilla.redhat.com/show_bug.cgi?id=1118804) to rework the init script at another time.

```
celery init v10.0.
Using config script: /etc/default/pulp_workers
celery multi v3.1.11 (Cipater)
> Starting nodes...
        > reserved_resource_worker-0@bmbouter-pulp-beta24-testing-2: Usage: /usr/lib/python2.6/site-packages/celery/bin/celery.pyc worker [options] 

/usr/lib/python2.6/site-packages/celery/bin/celery.pyc: error: option --umask: invalid integer value: '--pidfile=/var/run/pulp/reserved_resource_worker-0.pid'
* Child terminated with errorcode 2
FAILED
        > reserved_resource_worker-1@bmbouter-pulp-beta24-testing-2: Usage: /usr/lib/python2.6/site-packages/celery/bin/celery.pyc worker [options] 

/usr/lib/python2.6/site-packages/celery/bin/celery.pyc: error: option --umask: invalid integer value: '--pidfile=/var/run/pulp/reserved_resource_worker-1.pid'
* Child terminated with errorcode 2
FAILED
        > 18@bmbouter-pulp-beta24-testing-2: Usage: /usr/lib/python2.6/site-packages/celery/bin/celery.pyc worker [options] 

/usr/lib/python2.6/site-packages/celery/bin/celery.pyc: error: option --umask: invalid integer value: '--pidfile=/var/run/pulp/18.pid'
* Child terminated with errorcode 2
FAILED
```