Sort direction for selection depth wrong when doing best-hold selection

Due to a five-character error in commit 6b53189a9 that implemented custom best-hold selection sort orders, the sorting direction for the hold selection depth is ascending, not descending.

This is a mistake: the intention is that holds that have a more limited selection depth (i.e., have a higher value for action.hold_request.selection_depth) be preferred over ones that have a broader selection depth (i.e., have a lower value for the column). The reasoning is that holds that have a broader depth also presumably have overall more copies that could fill the hold. This is particularly applicable when soft boundaries are being used.