<!--- Verify first that your feature was not already discussed on GitHub -->
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##### SUMMARY
<!--- Describe the new feature/improvement briefly below -->
Currently it's not possible to specify disks to be included in the snapshot, always all disks are used.

##### ISSUE TYPE
- Feature Idea

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
ovirt_snapshot

##### ADDITIONAL INFORMATION
<!--- Describe how the feature would be used, why it is needed and what it would solve -->

<!--- Paste example playbooks or commands between quotes below -->
Could look like:
```yaml
ovirt_snapshot:
  description: My snap
  vm_name: myvm
  disks:
    - id: 123
    - id: 456
```

or 

```yaml
ovirt_snapshot:
  description: My snap
  vm_name: myvm
  disks:
    - name: myvm_disk_db
    - name: myvm_disk_store
```

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

vm_name=dict(required=True),
        snapshot_id=dict(default=None),
        disk_id=dict(default=None),
        disk_name=dict(default=None),
        description=dict(default=None),
        download_image_path=dict(default=None),
        upload_image_path=dict(default=None),
        keep_days_old=dict(default=None, type='int'),
        use_memory=dict(
            default=None,
            type='bool',
            aliases=['restore_memory', 'save_memory'],
        ),
    )
    module = AnsibleModule(
        argument_spec=argument_spec,
        supports_check_mode=True,
        required_if=[
            ('state', 'absent', ['snapshot_id']),
            ('state', 'restore', ['snapshot_id']),
        ]
    )
    check_sdk(module)
    ret = {}
    vm_name = module.params.get('vm_name')
    auth = module.params['auth']
    connection = create_connection(auth)
    vms_service = connection.system_service().vms_service()
    vm = search_by_name(vms_service, vm_name)
    if not vm: