[Ubuntu-2285]:"Horizon not working due to same uuid for two subnets "

See two subnets with same UUID:

7aaefc8a-37b7-4217-9483-24bcd83d0a8b

ValueError: Multiple matches were returned for that id: [<Subnet: {u'name': u'sub-1', u'enable_dhcp': True, u'network_id': u'5f6a6bcc-e68e-4b6d-b83a-44cf0fd5f6c5', u'tenant_id': u'0bb9908c61714470b799a4d5795fc344', u'dns_nameservers': [], u'allocation_pools': [{u'start': u'10.10.10.2', u'end': u'10.10.10.254'}], u'gateway_ip': u'10.10.10.1', u'ip_version': 4, u'host_routes': [], u'cidr': u'10.10.10.0/24', u'id': u'7aaefc8a-37b7-4217-9483-24bcd83d0a8b', 'ipver_str': 'IPv4'}>, <Subnet: {u'name': u'sub-4', u'enable_dhcp': True, u'network_id': u'5f6a6bcc-e68e-4b6d-b83a-44cf0fd5f6c5', u'tenant_id': u'0bb9908c61714470b799a4d5795fc344', u'dns_nameservers': [], u'allocation_pools': [{u'start': u'10.10.10.2', u'end': u'10.10.10.254'}], u'gateway_ip': u'10.10.10.1', u'ip_version': 4, u'host_routes': [], u'cidr': u'10.10.10.0/24', u'id': u'7aaefc8a-37b7-4217-9483-24bcd83d0a8b', 'ipver_str': 'IPv4'}>].

root@nodea5:~# neutron net-show 5f6a6bcc-e68e-4b6d-b83a-44cf0fd5f6c5
+-------------------------+-----------------------------------------------------------------------------------------------------------------+
| Field | Value |
+-------------------------+-----------------------------------------------------------------------------------------------------------------+
| admin_state_up | True |
| contrail:fq_name | default-domain |
| | admin |
| | vn-3 |
| contrail:instance_count | 0 |
| contrail:subnet_ipam | {"subnet_cidr": "10.10.10.0/24", "ipam_fq_name": ["default-domain", "admin", "test"]} |
| | {"subnet_cidr": "20.20.20.0/24", "ipam_fq_name": ["default-domain", "admin", "test"]} |
| | {"subnet_cidr": "30.30.30.0/24", "ipam_fq_name": ["default-domain", "admin", "test"]} |
| | {"subnet_cidr": "10.10.10.0/24", "ipam_fq_name": ["default-domain", "default-project", "default-network-ipam"]} |
| id | 5f6a6bcc-e68e-4b6d-b83a-44cf0fd5f6c5 |
| name | vn-3 |
| router:external | False |
| shared ...

This is negative test. Making the priority as low

We should disallow creating two subnets with same/overlapping cidr on a network regardless of ipam.

Hitting the issue again on R1.1 # 30 .

very old issue, reported on 1.1 twig, can we confirm with latest or 4.0 or newer throttle we still want bug fixes