BUG REPORT INFORMATION

Description

1. sonic-mgmt test suite stop at "Force stop RIBD to simulate GR" of bgp_gr_helper.yml
2. playbook command: ansible-playbook -vvvi lab -l sonicdev test_sonic.yml -e "testcase_name=bgp_gr_helper testbed_type=t1 testbed_file=testbed.csv testbed_name=vms-t1 ptf_host=ptf_vmt1"
3. ansible-playbook 2.8.7 can't got eos_login and eos_password even if they has been defined in sonic-mgmt/ansible/group_vars/all/creds.yml.

Steps to reproduce the issue:

1. start-vms for T1 test

2. add-topo T1 topology

3. gen-mg t1 minigraph

4. deploy-mg to DUT.

5. Run: ansible-playbook -vvvi lab -l sonicdev test_sonic.yml -e "testcase_name=bgp_gr_helper testbed_type=t1 testbed_file=testbed.csv testbed_name=vms-t1 ptf_host=ptf_vmt1"

6. got below error message @ Force stop RIBD to simulate GR step.
   TASK [test : Force stop RIBD to simulate GR.] ***************************************************************************************************************************
   task path: /var/sqa/sonic-mgmt/ansible/roles/test/tasks/bgp_gr_helper.yml:49
   Thursday 09 January 2020 01:19:27 +0000 (0:00:00.782) 0:01:01.587 ******
   Using module file /usr/local/lib/python2.7/dist-packages/ansible/modules/commands/command.py
   Pipelining is enabled.
   <192.168.59.47> ESTABLISH SSH CONNECTION FOR USER: None
   <192.168.59.47> SSH: EXEC ssh -o ControlMaster=auto -o ControlPersist=120s -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -o StrictHostKeyChecking=no -o KbdInteractiveAuthentication=no -o PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey -o PasswordAuthentication=no -o ConnectTimeout=10 -o ControlPath=/var/sqa/.ansible/cp/a46f235326 192.168.59.47 '/bin/sh -c '"'"'/usr/bin/python && sleep 0'"'"''
   fatal: [sonicdev]: UNREACHABLE! => {
   "changed": false,
   "msg": "Data could not be sent to remote host "192.168.59.47". Make sure this host can be reached over ssh: Warning: Permanently added '192.168.59.47' (ECDSA) to the list of known hosts.\r\nPermission denied (publickey,keyboard-interactive).\r\n",
   "unreachable": true
   }

Additional information you deem important:
sonic-mgmt/ansible/group_vars/all/creds.yml info:

eos_default_login: admin
eos_default_password: ''
eos_login: admin
eos_password: 123456
eos_root_password: 123456
sonic_default_password:
sonic_login: admin
sonic_password: password