Openstackclient does not support the --force parameter for quota setting

Description
===========

The --force parameter is missing from the "openstack quota set" command.
As a result of this, there is no way to set the --compute quotas to values less that the used/reserved using the openstackclient.

On the other hand, the command "nova quota-update" supports the use of a force option (--force).
This allows the admins to set the quota to values lower than the used/reserved.

 --force Whether force update the quota even if the
                               already used and reserved exceeds the new
                               quota.

Steps to reproduce
==================

It seems that setting volume and networking quota to values lower than the used is allowed.

E.g.

Even after creating two volumes, the --volumes quota can be set to 1 without problems:

stack@devstack-010:~$ openstack volume list
+--------------------------------------+--------------+-----------+------+-------------+
| ID | Name | Status | Size | Attached to |
+--------------------------------------+--------------+-----------+------+-------------+
| 252a0d84-9456-49c2-931c-074119259ac8 | test_volume1 | available | 15 | |
| a84cd191-4c25-4c36-b28a-60da15ed4719 | test_volume | available | 20 | |
+--------------------------------------+--------------+-----------+------+-------------+
stack@devstack-010:~$ openstack quota set --volumes 1 admin

The same applies for floating ips:

stack@devstack-010:~$ openstack floating ip list -c ID -c "Floating IP Address" -c Project
+--------------------------------------+---------------------+----------------------------------+
| ID | Floating IP Address | Project |
+--------------------------------------+---------------------+----------------------------------+
| 798dad32-a834-4364-ac80-4d9eabd55f0d | 172.24.4.5 | a9dc783f37764750a01b3e3197959529 |
| eee43cbf-9022-48a5-83dc-22db15e967d9 | 172.24.4.9 | a9dc783f37764750a01b3e3197959529 |
+--------------------------------------+---------------------+----------------------------------+
stack@devstack-010:~$ openstack quota set --floating-ips 1 a9dc783f37764750a01b3e3197959529

But when setting the --instances quota:

stack@devstack-010:~$ openstack server list -c ID -c Name -c Status
+--------------------------------------+---------------+--------+
| ID | Name | Status |
+--------------------------------------+---------------+--------+
| 8573f7a7-41c5-49ab-ab91-40a0126350a0 | ttesting-vm-2 | ACTIVE |
| cf96fdde-668b-4d3e-96cd-21d6066ac46a | ttesting-vm-1 | ACTIVE |
+--------------------------------------+---------------+--------+
stack@devstack-010:~$ openstack quota set --instances 1 a9dc783f37764750a01b3e3197959529
Quota limit 1 for instances must be greater than or equal to already used and reserved 2. (HTTP 400) (Request-ID: req-e8ba1e66-7f7c-4e77-8a91-2a134fcfc7c9)

Expected result
===============

The option to force the update should be available since the nova quota-set supports it.

Actual result
=============

There is no way to set the quota to the desired value using the openstackclient.

Comments
========

It would be great to have the force option, as it allows the operators to stop the creation of new VMs in user projects.