Get container_facts failing on localhost

Hi,

Kolla-ansible is trying to check container_facts, but python docker library is not installed on localhost (deployment host) by default.

TASK [prechecks : Checking host OS release or version] ************************************************************************************************************************************************************
skipping: [ceph0]
skipping: [ceph1]
skipping: [ceph2]
skipping: [localhost]
skipping: [controller0]
skipping: [controller1]
skipping: [compute0]
skipping: [compute1]

TASK [prechecks : include_tasks] **********************************************************************************************************************************************************************************
included: /opt/kolla-ansible/ansible/roles/prechecks/tasks/timesync_checks.yml for ceph0, ceph1, ceph2, localhost, controller0, controller1, compute0, compute1

TASK [prechecks : Get container facts] ****************************************************************************************************************************************************************************
An exception occurred during task execution. To see the full traceback, use -vvv. The error was: ModuleNotFoundError: No module named 'docker'
fatal: [localhost]: FAILED! => {"changed": false, "module_stderr": "Traceback (most recent call last):\n File \"/home/ubuntu/.ansible/tmp/ansible-tmp-1624454249.8777878-29781-115946227316597/AnsiballZ_kolla_container_facts.py\", line 102, in <module>\n _ansiballz_main()\n File \"/home/ubuntu/.ansible/tmp/ansible-tmp-1624454249.8777878-29781-115946227316597/AnsiballZ_kolla_container_facts.py\", line 94, in _ansiballz_main\n invoke_module(zipped_mod, temp_path, ANSIBALLZ_PARAMS)\n File \"/home/ubuntu/.ansible/tmp/ansible-tmp-1624454249.8777878-29781-115946227316597/AnsiballZ_kolla_container_facts.py\", line 40, in invoke_module\n runpy.run_module(mod_name='ansible.modules.kolla_container_facts', init_globals=None, run_name='__main__', alter_sys=True)\n File \"/usr/lib/python3.8/runpy.py\", line 207, in run_module\n return _run_module_code(code, init_globals, run_name, mod_spec)\n File \"/usr/lib/python3.8/runpy.py\", line 97, in _run_module_code\n _run_code(code, mod_globals, init_globals,\n File \"/usr/lib/python3.8/runpy.py\", line 87, in _run_code\n exec(code, run_globals)\n File \"/tmp/ansible_kolla_container_facts_payload_8sraqpzw/ansible_kolla_container_facts_payload.zip/ansible/modules/kolla_container_facts.py\", line 18, in <module>\nModuleNotFoundError: No module named 'docker'\n", "module_stdout": "", "msg": "MODULE FAILURE\nSee stdout/stderr for the exact error", "rc": 1}