Small fix in the worker where a default value was passed to getStoreConfig

I think you wanted to pass the default vallue to the Mage::getStoreConfig method. However (at least in 1.7) this is not possible and throws an exception.

If I am missing something or my assumption is wrong please correct me.
Merge pull request #2 from Fraak/patch-1

Small fix in the worker with getting the default queue