<!--- Verify first that your issue is not already reported on GitHub -->
<!--- Also test if the latest release and devel branch are affected too -->
<!--- Complete *all* sections as described, this form is processed automatically -->

##### SUMMARY
<!--- Explain the problem briefly below -->
Getting FATAL error when VM cluster contains ESX hosts in non-responding state

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
vmware_vmkernel_facts
##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
2.8.3
```

##### CONFIGURATION
<!--- Paste verbatim output from "ansible-config dump --only-changed" between quotes -->
```paste below

```

##### OS / ENVIRONMENT
<!--- Provide all relevant information below, e.g. target OS versions, network device firmware, etc. -->
VCS 6.5

##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->
simple playbook to query the vmkernel facts
<!--- Paste example playbooks or commands between quotes below -->
```yaml
- name: Gather vmkernel facts from cluster
    vmware_vmkernel_facts:
      cluster_name: '{{vm_cluster}}'
      validate_certs: no
    delegate_to: localhost
    register: vmk_out
    ignore_errors: yes
```

<!--- HINT: You can paste gist.github.com links for larger files -->

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->
standard output 

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->
```
{
    "exception": "Traceback (most recent call last):\n  File \"/root/.ansible/tmp/ansible-tmp-1569306301.15-75561088679807/AnsiballZ_vmware_vmkernel_facts.py\", line 114, in <module>\n    _ansiballz_main()\n  File \"/root/.ansible/tmp/ansible-tmp-1569306301.15-75561088679807/AnsiballZ_vmware_vmkernel_facts.py\", line 106, in _ansiballz_main\n    invoke_module(zipped_mod, temp_path, ANSIBALLZ_PARAMS)\n  File \"/root/.ansible/tmp/ansible-tmp-1569306301.15-75561088679807/AnsiballZ_vmware_vmkernel_facts.py\", line 49, in invoke_module\n    imp.load_module('__main__', mod, module, MOD_DESC)\n  File \"/tmp/ansible_vmware_vmkernel_facts_payload_XR_16X/__main__.py\", line 201, in <module>\n  File \"/tmp/ansible_vmware_vmkernel_facts_payload_XR_16X/__main__.py\", line 196, in main\n  File \"/tmp/ansible_vmware_vmkernel_facts_payload_XR_16X/__main__.py\", line 109, in __init__\n  File \"/tmp/ansible_vmware_vmkernel_facts_payload_XR_16X/__main__.py\", line 119, in get_all_vmks_by_service_type\n  File \"/tmp/ansible_vmware_vmkernel_facts_payload_XR_16X/__main__.py\", line 146, in query_service_type_for_vmks\nAttributeError: 'NoneType' object has no attribute 'selectedVnic'\n",
    "_ansible_no_log": false,
    "_ansible_delegated_vars": {
        "ansible_host": "localhost"
    },
    "module_stderr": "Traceback (most recent call last):\n  File \"/root/.ansible/tmp/ansible-tmp-1569306301.15-75561088679807/AnsiballZ_vmware_vmkernel_facts.py\", line 114, in <module>\n    _ansiballz_main()\n  File \"/root/.ansible/tmp/ansible-tmp-1569306301.15-75561088679807/AnsiballZ_vmware_vmkernel_facts.py\", line 106, in _ansiballz_main\n    invoke_module(zipped_mod, temp_path, ANSIBALLZ_PARAMS)\n  File \"/root/.ansible/tmp/ansible-tmp-1569306301.15-75561088679807/AnsiballZ_vmware_vmkernel_facts.py\", line 49, in invoke_module\n    imp.load_module('__main__', mod, module, MOD_DESC)\n  File \"/tmp/ansible_vmware_vmkernel_facts_payload_XR_16X/__main__.py\", line 201, in <module>\n  File \"/tmp/ansible_vmware_vmkernel_facts_payload_XR_16X/__main__.py\", line 196, in main\n  File \"/tmp/ansible_vmware_vmkernel_facts_payload_XR_16X/__main__.py\", line 109, in __init__\n  File \"/tmp/ansible_vmware_vmkernel_facts_payload_XR_16X/__main__.py\", line 119, in get_all_vmks_by_service_type\n  File \"/tmp/ansible_vmware_vmkernel_facts_payload_XR_16X/__main__.py\", line 146, in query_service_type_for_vmks\nAttributeError: 'NoneType' object has no attribute 'selectedVnic'\n",
    "changed": false,
    "module_stdout": "",
    "rc": 1,
    "msg": "MODULE FAILURE\nSee stdout/stderr for the exact error"
}
```

esxi_hostname:
    description:
    - ESXi hostname.
    - VMKernel information about this ESXi server will be returned.
    - If C(cluster_name) is not given, this parameter is required.
    type: str
extends_documentation_fragment: vmware.documentation
'''
EXAMPLES = r'''
- name: Gather VMKernel info about all ESXi Host in given Cluster
  vmware_vmkernel_info:
    hostname: '{{ vcenter_hostname }}'
    username: '{{ vcenter_username }}'
    password: '{{ vcenter_password }}'
    cluster_name: cluster_name
  delegate_to: localhost
  register: cluster_host_vmks
- name: Gather VMKernel info about ESXi Host
  vmware_vmkernel_info:
    hostname: '{{ vcenter_hostname }}'
    username: '{{ vcenter_username }}'
    password: '{{ vcenter_password }}'
    esxi_hostname: '{{ esxi_hostname }}'
  delegate_to: localhost
  register: host_vmks
'''
RETURN = r'''
host_vmk_info:
    description: metadata about VMKernel present on given host system
    returned: success