##### 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}

```

"""
        Find unique virtual machine either by UUID, MoID or Name.
        Returns: virtual machine object if found, else None.
        """
        vm_obj = None
        user_desired_path = None
        use_instance_uuid = self.params.get('use_instance_uuid') or False
        if self.params['uuid'] and not use_instance_uuid:
            vm_obj = find_vm_by_id(self.content, vm_id=self.params['uuid'], vm_id_type="uuid")
        elif self.params['uuid'] and use_instance_uuid:
            vm_obj = find_vm_by_id(self.content,
                                   vm_id=self.params['uuid'],
                                   vm_id_type="instance_uuid")
        elif self.params['name']:
            objects = self.get_managed_objects_properties(vim_type=vim.VirtualMachine, properties=['name'])
            vms = []
            for temp_vm_object in objects:
                if len(temp_vm_object.propSet) != 1:
                    continue
                for temp_vm_object_property in temp_vm_object.propSet:
                    if temp_vm_object_property.val == self.params['name']:
                        vms.append(temp_vm_object.obj)
                        break
            
            
            if len(vms) > 1:
                
                if self.params['folder'] is None: