[cisco-aci-plugin] the network created during connectivity check test is not removed after test

[Ruslan Khozinov]

1. deploy an env with 1 compute + 1 contoller
2. run connectivity health-check test
3. go to Horizon>Project>Network>Network Topology

For my env after deploy I saw only two default network,
+--------------------------------------+-----------------------------------+-------------------------------------------------------+
| id | name | subnets |
+--------------------------------------+-----------------------------------+-------------------------------------------------------+
| b72276b9-d515-4e09-bc94-8b05cb8039e8 | net04_ext | f21d4556-3aea-40dc-bdc2-9358e5033687 10.109.1.0/24 |
| acc1dcd4-8fde-4541-849a-2029c266ec7e | net04 | c89ac17a-c62d-4cb4-add5-4a31cfefff55 192.168.111.0/24 |
+--------------------------------------+-----------------------------------+-------------------------------------------------------+

and after the test execution (note: the test fails) I saw one more network with ost1_prefix.

+--------------------------------------+-----------------------------------+-------------------------------------------------------+
| id | name | subnets |
+--------------------------------------+-----------------------------------+-------------------------------------------------------+
| 199adc46-d866-4466-908c-84a6afa3b144 | ost1_test-server-smoke-1404665048 | 3e0017c0-19c1-4f3a-b9a6-9de581eaeccc 10.0.7.0/24 |
| b72276b9-d515-4e09-bc94-8b05cb8039e8 | net04_ext | f21d4556-3aea-40dc-bdc2-9358e5033687 10.109.1.0/24 |
| acc1dcd4-8fde-4541-849a-2029c266ec7e | net04 | c89ac17a-c62d-4cb4-add5-4a31cfefff55 192.168.111.0/24 |
+--------------------------------------+-----------------------------------+-------------------------------------------------------+

But the " ost1_test-server-smoke-1404665048" network should be removed after test execution.