Quota code doesn't work with instance soft-delete

There are really two issues here:

1. Soft-delete isn't handled at all (since deallocation of instance occurs int the compute-manager but quota handling occurs in the compute-api).

2. Overriding (1), soft-deletes should probably not count against quotas at all since the user has no visibility or control of an instance once it has been deleted.

If we wanted to avoid the scenario of someone spinning up and spinning down a whole bunch of servers, a separate quota should be used, perhaps builds-per-hour.