volume quota is not released on delete

So i dropped my default quota_volumes down to 1 to show this example of the problem on a clean devstack.

clayg@cfsyn28:~$ cinder create 1
clayg@cfsyn28:~$ cinder list
+--------------------------------------+-----------+--------------+------+-------------+-------------+
| ID | Status | Display Name | Size | Volume Type | Attached to |
+--------------------------------------+-----------+--------------+------+-------------+-------------+
| e2cd05e9-847a-4257-b13e-886d5991ce8e | available | None | 1 | None | |
+--------------------------------------+-----------+--------------+------+-------------+-------------+
clayg@cfsyn28:~$ cinder create 1
ERROR: VolumeLimitExceeded: Maximum number of volumes allowed (1) exceeded (HTTP 413) (Request-ID: req-8c70a243-dd89-4c47-9e9d-093b7efa3c1d)
clayg@cfsyn28:~$ cinder delete e2cd05e9-847a-4257-b13e-886d5991ce8e
clayg@cfsyn28:~$ cinder list
+--------------------------------------+----------+--------------+------+-------------+-------------+
| ID | Status | Display Name | Size | Volume Type | Attached to |
+--------------------------------------+----------+--------------+------+-------------+-------------+
| e2cd05e9-847a-4257-b13e-886d5991ce8e | deleting | None | 1 | None | |
+--------------------------------------+----------+--------------+------+-------------+-------------+
clayg@cfsyn28:~$ cinder list

clayg@cfsyn28:~$ cinder create 1
ERROR: VolumeLimitExceeded: Maximum number of volumes allowed (1) exceeded (HTTP 413) (Request-ID: req-2b6673f0-f724-4963-b4d2-627e37c4f538)

I think something like making a reservation for a negative value in volume.api.delete would get things moving in the right direction:

reservations = QUOTAS.reserve(context, volumes=-1, gigabytes=-size)

also, it'd be nice of there was something like 'nova-manage project quota list' but for the cinder db, or maybe an admin api extension would be better? Maybe I just missed something. Is it easy to disable quota all together? I didn't see anything like cinder.quota.NullQuotaDriver.