Description
I am trying to run the ecmp test without success.
I have tried several commands to launch the test, each of which fails in an unexpected way.

Steps to reproduce the issue:

1. ansible-playbook test_sonic.yml -vvv -i lab --limit ch1-dut, --become --tags ecmp --extra-vars "testbed_type=t1 vm_hosts=[VM0101,VM0102,VM0103] vm_source={VM0100} [ipv6=True]" | tee /data/testlogs/ecmp/pb.log
   This is the way the documentation says to launch the test.
   But the test bails out right after the Gathering Facts task.

2. ansible-playbook test_sonic.yml -vvv -i lab --limit ch1-dut -e testcase_name=ecmp -e testbed_name=chill-t1 --extra-vars "testbed_type=t1 vm_hosts=[VM0110,VM0111,VM0112] vm_source={VM0100} [ipv6=True]"
   This command to launch the test goes much further, but eventually fails:
   TASK [test : Configure VMs to add loopback interface] *******************************************************
   task path: /data/ansible/roles/test/tasks/ecmp.yml:45
   Wednesday 02 December 2020 13:04:09 +0000 (0:00:00.192) 0:00:20.656 ****
   Using module file /data/ansible/library/configure_vms.py
   Pipelining is enabled.
   <10.250.0.103> ESTABLISH SSH CONNECTION FOR USER: cisco
   <10.250.0.103> SSH: EXEC sshpass -d10 ssh -o ControlMaster=auto -o ControlPersist=120s -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -o StrictHostKeyChecking=no -o 'User="cisco"' -o ConnectTimeout=10 -o ControlPath=/root/.ansible/cp/6b7f686bbd 10.250.0.103 '/bin/sh -c '"'"'/usr/bin/python && sleep 0'"'"''
   <10.250.0.103> (1, '', 'Traceback (most recent call last):\n File "", line 114, in \n File "", line 106, in _ansiballz_main\n File "", line 49, in invoke_module\n File "/tmp/ansible_configure_vms_payload_SKUjwe/main.py", line 21, in \nImportError: No module named paramiko\n')

3. py.test saitests/ecmp_test.py --testbed=chill-t1 --inventory=/data/ansible/lab --testbed_file=../ansible/testbed.csv --host-pattern=chill-t1 --module-path=../ansible/library -v
   This one also fails:
   __________________________________ ERROR collecting saitests/ecmp_test.py ___________________________________
   ImportError while importing test module '/data/tests/saitests/ecmp_test.py'.
   Hint: make sure your test modules/packages have valid Python names.
   Traceback:
   saitests/ecmp_test.py:10: in
   import sai_base_test
   saitests/sai_base_test.py:25: in
   import switch_sai_thrift
   E ImportError: No module named switch_sai_thrift

Describe the results you expected:
I expected perhaps one of these tests to execute.

Additional information you deem important:

**Output of `show version`:**

```

SONiC Software Version: SONiC.master.424-ebdfb4be
Distribution: Debian 10.4
Kernel: 4.19.0-9-2-amd64
Build commit: ebdfb4b
Build date: Wed Jul 22 17:17:01 UTC 2020
Built by: johnar@jenkins-worker-9

Platform: x86_64-kvm_x86_64-r0
HwSKU: Force10-S6000
ASIC: vs
Serial Number: 000000
Uptime: 17:37:45 up 1 day, 3:58, 1 user, load average: 1.83, 2.74, 3.33
```