When bumping is required to free up enough bandwidth for a new
path there exists a short period of time when both the new path and
the soon to be bumped path are occupying the same bandwidth.
This means that the total amount of reserved bandwidth will exceed
maxReservableBwOut. When this happens the unreservedBwOut
attribute will be 0 and the overReservedBwOut attribute will be non-
zero to indicate by how much we are currently overcommitted. This
value should quickly drop back to zero as the bumping starts to
clear the lower holdingPriority calls.