SchedulerController: receive_completed before scheduling

[apfitzge]

Problem

• receive_completed is called immediately after scheduling...when it is very likely nothing (that was just scheduled) has completed.
• It is better to to call receive_completed sometime after the (potentially) long call to receive_and_buffer and before the next schedule.

Summary of Changes

Flip-flop the lines so that we receive_completed before scheduling (after receive_and_buffer)

Fixes #