##### SUMMARY
get_vm() method vmware.py module utility fails with KeyError if uuid is not in the module param from whch method is invoked

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
vmware.py module util

##### ANSIBLE VERSION
```
ansible 2.9.0.dev0
```

##### OS / ENVIRONMENT
Ubuntu 16

##### STEPS TO REPRODUCE
Creating new module. 'uuid' is not in my module arguments. 
Called get_vm() 

pyv = PyVmomi(module=module)
vm = pyv.get_vm()

##### EXPECTED RESULTS
Call should return vm_id if it exists

##### ACTUAL RESULTS
```
Get error
An exception occurred during task execution. To see the full traceback, use -vvv. The error was: KeyError: 'uuid'
fatal: [localhost]: FAILED! => {"changed": false, "module_stderr": "Traceback (most recent call last):\n  File
\"/home/vmware/.ansible/tmp/ansible-tmp-1565095783.75439-259726275713856/AnsiballZ_vmware_content_deploy_template.py\", line 125, in <module>\n    _ansiballz_main()\n  File \"/home/vmware/.ansible/tmp/ansible-tmp-1565095783.75439-259726275713856/AnsiballZ_vmware_content_deploy_template.py\", line 117, in _ansiballz_main\n    invoke_module(zipped_mod, temp_path, ANSIBALLZ_PARAMS)\n  File \"/home/vmware/.ansible/tmp/ansible-tmp-1565095783.75439-259726275713856/AnsiballZ_vmware_content_deploy_template.py\", line 51, in invoke_module\n    spec.loader.exec_module(module)\n  File \"<frozen importlib._bootstrap_external>\", line 665, in exec_module\n  File \"<frozen importlib._bootstrap>\", line 222, in _call_with_frames_removed\n  File \"/tmp/ansible_vmware_content_deploy_template_payload_69cftg21/__main__.py\", line 271, in <module>\n  File \"/tmp/ansible_vmware_content_deploy_template_payload_69cftg21/__main__.py\", line 241, in main\n  File \"/tmp/ansible_vmware_content_deploy_template_payload_69cftg21/ansible_vmware_content_deploy_template_payload.zip/ansible/module_utils/vmware.py\", line 891,
in get_vm\nKeyError: 'uuid'\n", "module_stdout": "", "msg": "MODULE FAILURE\nSee stdout/stderr for the exact error", "rc": 1}

```

kn = value_obj.key
        if cfm is not None and cfm.field:
            for f in cfm.field:
                if f.key == value_obj.key:
                    kn = f.name
                    
                    break
        facts['customvalues'][kn] = value_obj.value
    net_dict = {}
    vmnet = _get_vm_prop(vm, ('guest', 'net'))
    if vmnet:
        for device in vmnet:
            net_dict[device.macAddress] = list(device.ipAddress)
    if vm.guest.ipAddress:
        if ':' in vm.guest.ipAddress:
            facts['ipv6'] = vm.guest.ipAddress
        else:
            facts['ipv4'] = vm.guest.ipAddress
    ethernet_idx = 0
    for entry in vm.config.hardware.device:
        if not hasattr(entry, 'macAddress'):
            continue
        if entry.macAddress:
            mac_addr = entry.macAddress
            mac_addr_dash = mac_addr.replace(':', '-')
        else:
            mac_addr = mac_addr_dash = None
        if (hasattr(entry, 'backing') and hasattr(entry.backing, 'port') and
                hasattr(entry.backing.port, 'portKey') and hasattr(entry.backing.port, 'portgroupKey')):
            port_group_key = entry.backing.port.portgroupKey