Problem: unnecessary scoping in Scheduler.run
Problem: unnecessary scoping in Scheduler.run

As noticed by @stuarth https://github.com/PumpkinDB/PumpkinDB/pull/323/files#r125484271
the scoping was seem to be unnecessary.

Originally, it was there to satisfy borrowing rules, but as it turns out,
the code got simpler and this is no longer necessary.

Solution: remove this unnecessary scoping

PumpkinDB/PumpkinDB