Assert that memory held by rephist is freed

Assert that memory held by rephist is freed

The internal memory allocation and history object counters of the
reputation code can be used to verify the correctness of (part of) the
code. Using these counters revealed an issue where the memory allocation
counter is not decreased when the bandwidth arrays are freed.

A new function ensures the memory allocation counter is decreased when a
bandwidth array is freed.

This commit also removes an unnecessary cast which was found while
working on the code.