Recalculate quotes often to satisfy the ghost of WPeC past

This is a hack do avoid breaking themes that rely on this function to decide whether or not to display
the shipping calculator.  Sadly our logic flow recalculates quotes for the currently selected shipping method on checkout and overwrites all of the quotes in the cart.  When there is an error on checkout the quotes that where originally presented have been vanquished to the netherworld.  So we are going to recalculate every time this function is called, which hopefully is only when the checkout page is displayed.