##### 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}

```

"""
        Get datastore cluster managed object by name
        Args:
            datastore_cluster_name: Name of datastore cluster
        Returns: Datastore cluster managed object if found else None
        """
        data_store_clusters = get_all_objs(self.content, [vim.StoragePod])
        for dsc in data_store_clusters:
            if dsc.name == datastore_cluster_name:
                return dsc
        return None
    
    def find_resource_pool_by_name(self, resource_pool_name, folder=None):
        """
        Get resource pool managed object by name
        Args:
            resource_pool_name: Name of resource pool
        Returns: Resource pool managed object if found else None
        """
        if not folder:
            folder = self.content.rootFolder
        resource_pools = get_all_objs(self.content, [vim.ResourcePool], folder=folder)
        for rp in resource_pools:
            if rp.name == resource_pool_name:
                return rp
        return None
    def find_resource_pool_by_cluster(self, resource_pool_name='Resources', cluster=None):