Added subsys lock file to worker init script

This is required on RHEL style machines to properly handle run level changes.

You can read about it in more detail here which isn't the best documentation I know but the best I could find that validates why this change is necessary.

http://www.redhat.com/magazine/008jun05/departments/tips_tricks/

Just did a similar fix on mod_gearman's init scripts.

https://github.com/sni/mod_gearman/pull/47