fixing scoping issue for index sync

Fixes #106 .
I can move the thread into this class's `execute()` method, but I'm curious as to why a timeout would occur here. When this startup method is invoked, it's during the servlet init phase, so it will block the application from becoming available until it completes. Is that what you're trying to improve here?

Basically, my concern is that if you are seeing timeouts here, I'm not sure if threading will help.