Remove a needless min_heap_shift_up_() call Previously, every call to min_heap_shift_down_() would invoke min_heap_shift_up_() at the end. This used to be necessary in the first version of the minheap code, since min_heap_erase() would call min_heap_shift_down_() unconditionally. But when patch 8b7a3b36763 from Marko Kreen fixed min_heap_erase() to be more sensible, we left the weird behavior of min_heap_shift_down_() in place. Fortunately, "cui" noticed this and reported it on Niels's blog.