Unable to create same Pvt Network per tenant.

Description :
   Unable to create same Pvt Network per tenant.

Detail Description:

  While creating the same Pvt network for two tenants ( Tanenant A and B ) for the second tenant it is saying error message "Error: Failed to create subnet "192.168.98.0/24" for network "192.168.98.0": Invalid input for operation: Requested subnet with cidr: 192.168.98.0/24 for network: dc7b89a5-b655-4ca9-807b-ba9f8c124377 overlaps with another subnet."
But as a use case tenanets can hve there own pvt network.

(a) Repro steps:
1. Create two network profiles one for tenant A and Another for tenant B.
2. Create network A in tenant A with subnet 192.168.51.0/24
3. Create network B in tenant B with subnet 192.168.51.0/24

(b) Reproducibility: yes

(c) Expected behaviour : Pvt Networks are based on tenant. Different tenats can have same subnet as part of there Pvt network.

(d) Workaround: No.

(e) Recovery steps: None.

(f) Impact: Tenant can't have his own subnet if same subnet is used by another tenant before him.

Logs :

2013-10-28 04:40:29 ERROR [quantum.db.db_base_plugin_v2] Validation for CIDR: 192.168.98.0/24 failed - overlaps with subnet dedd2ade-9248-4e6b-ad82-71046d0eedb2 (CIDR: 192.168.98.0/24)
2013-10-28 04:40:29 ERROR [quantum.api.v2.resource] create failed
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/quantum/api/v2/resource.py", line 82, in resource
    result = method(request=request, **args)
  File "/usr/lib/python2.7/dist-packages/quantum/api/v2/base.py", line 369, in create
    obj = obj_creator(request.context, **kwargs)
  File "/usr/lib/python2.7/dist-packages/quantum/plugins/cisco/n1kv/n1kv_quantum_plugin.py", line 1432, in create_subnet
    sub = super(N1kvQuantumPluginV2, self).create_subnet(context, subnet)
  File "/usr/lib/python2.7/dist-packages/quantum/db/db_base_plugin_v2.py", line 1113, in create_subnet
    self._validate_subnet_cidr(context, network, s['cidr'])
  File "/usr/lib/python2.7/dist-packages/quantum/db/db_base_plugin_v2.py", line 745, in _validate_subnet_cidr
    raise q_exc.InvalidInput(error_message=err_msg)
InvalidInput: Invalid input for operation: Requested subnet with cidr: 192.168.98.0/24 for network: dc7b89a5-b655-4ca9-807b-ba9f8c124377 overlaps with another subnet.