Refine behavior of ApprovalSessionBean.getRemainingNumberOfApprovals(int)

Customer has required the following behavior from ApprovalSessionBean.getRemainingNumberOfApprovals(int)

Modify getRemainingNumberOfApprovals so that 
if NumberOfApprovals (noa) > 0 and not expired -> return noa 
if noa > 0 and expired -> throw exception 
if noa == 0 -> return 0 
if noa <0 -> return -1

This change in behavior should be noted in the upgrade document, as it effects behavior for the corresponding WS method.