Fix deploy errors when service isn't running

Allow the stop command for poky/varnish to exit successfully when their
respective processes aren't running.

Fixes deploy issue on cold system

```
*** [err :: qa.poky.huddler.com] /var/www/poky/releases/20130606043610/scripts/poky.init.sh: line 45: kill: (30972) - No such process
```
```
*** [err :: qa.poky.huddler.com] /var/www/poky/releases/20130606050406/scripts/varnish.init.sh: line 53: kill: (31023) - No such process
```