[Vrf] test_vrf fails due to missing attributes in topo_t0.yml

[AndriiLozovyi]

Description:
After running test_vrf some of test cases fail with such error:
"AnsibleUndefinedVariable: 'dict object' has no attribute 'podset_number'".
The reason is that these attributes were deleted from topo_t0.yml by commit #1233

    podset_number: 200
    tor_number: 16
    tor_subnet_number: 2
    max_tor_subnet_number: 16
    tor_subnet_size: 128
    spine_asn: 65534
    leaf_asn_start: 64600
    tor_asn_start: 65100
    failure_rate: 0

These attributes is mainly used in test_vrf by vrf_fib.j2

Steps to reproduce the issue:

1. Deploy t0 topology.
2. Deploy minigrapgh on DUT
3. Run test_vrf.py

Describe the results you received:

E           RunAnsibleModuleFail: run module template failed, Ansible Results =>
E           {"changed": false, "failed": true, "msg": "AnsibleUndefinedVariable: 'dict object' has no attribute 'podset_number'"}

vrf/test_vrf.py::TestVrfIsolation::test_neigh_isolate_vrf1_from_vrf2 ERROR                                                                                       
vrf/test_vrf.py::TestVrfIsolation::test_neigh_isolate_vrf2_from_vrf1 ERROR                                                                                       
vrf/test_vrf.py::TestVrfIsolation::test_fib_isolate_vrf1_from_vrf2 ERROR                                                                                        
vrf/test_vrf.py::TestVrfIsolation::test_fib_isolate_vrf2_from_vrf1 ERROR

Describe the results you expected:

vrf/test_vrf.py::TestVrfIsolation::test_neigh_isolate_vrf1_from_vrf2 PASSED
vrf/test_vrf.py::TestVrfIsolation::test_neigh_isolate_vrf2_from_vrf1 PASSED
vrf/test_vrf.py::TestVrfIsolation::test_fib_isolate_vrf1_from_vrf2 PASSED
vrf/test_vrf.py::TestVrfIsolation::test_fib_isolate_vrf2_from_vrf1 PASSED

Additional information you deem important:

**Output of `show version`:**

```
SONiC Software Version: SONiC.master.22-dirty-20201030.044825
Distribution: Debian 10.6
Kernel: 4.19.0-9-2-amd64
Build commit: b132ca09
```

**Attach debug file `sudo generate_dump`:**

```
(paste your output here)
```

[SavchukRomanLv]

@lguohan could you please take a look? Thanks in advance.