Comment 4 for bug 1347156

I think it's the cooperation between 23a27e47 and cbbb9de5

in cbbb9de5, object is not used and it directly use DB returned value, so it's no problem
and 23a27e47 used object instead

@obj_base.remotable_classmethod
    def deallocate(cls, context, address):
        db.floating_ip_deallocate(context, address)

the deallocate function didn't return the value which is supposed to be returned
make every quota rollbacked