[BaseURL] serviceLocation is a request attribute, not an event attribute

Created by: davemevans

We are currently testing BaseURL switching and it seems to be fairly broken by some changes that have happened in the ScheduleController since BaseURL was originally implemented. More details to follow as we have them, and I'll open a holding issue now.

This one, though, has always been there and is definitely incorrect. The serviceLocation attribute belongs to a request and will never be found on the event. Without this fix, failed requests will never be retried on a new BaseURL. With it, for now, they still won't be rerequested as there are other problems with request replacement.