fixed missing parameter for chown in syslog-ng runit script

There's a missing parameter in syslog-ng's runit script. I noticed this while doing a 'ps'. Not sure whats the impact on the overall container.
```
root        95  0.0  0.0    188    32 ?        S    18:23   0:00 /usr/bin/runsvdir -P /etc/service log: ..........................................................................................................................................................................................................................................................................................................................chown: missing operand after 'root:adm' Try 'chown --help' for more information.
```