##### SUMMARY
add_host will return 'changed' for every invocation, it does not matter if the host already existed and no changes were actually made to inventory

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
add_host
##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
2.7, 2.8, 2.9, 2.10
```

##### 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. -->
all

##### STEPS TO REPRODUCE

Simplest example, but also happens when specifying variables and/or groups

test.yml
```yaml
- hosts: localhost
  gather_facts: false
  tasks:
    - add_host: name=testhost
```
test_inv.ini
```ini
testhost
```
run:
``` ansible-playbook -i test_inv.ini test.yml```

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

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->
```
 _________________
< TASK [add_host] >
 -----------------
       \   ,__,
        \  (oo)____
           (__)    )\
              ||--|| *

OK: [localhost]
```

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->

<!--- Paste verbatim command output between quotes -->
```paste below
 _________________
< TASK [add_host] >
 -----------------
       \   ,__,
        \  (oo)____
           (__)    )\
              ||--|| *

changed: [localhost]
```

else:
                msg = 'no connection, nothing to reset'
        else:
            raise AnsibleError("invalid meta action requested: %s" % meta_action, obj=task._ds)
        result = {'msg': msg}
        if skipped:
            result['skipped'] = True
        else:
            result['changed'] = False
        display.vv("META: %s" % msg)
        return [TaskResult(target_host, task, result)]
    def get_hosts_left(self, iterator):
        ''' returns list of available hosts for this iterator by filtering out unreachables '''
        hosts_left = []
        for host in self._hosts_cache:
            if host not in self._tqm._unreachable_hosts:
                try:
                    hosts_left.append(self._inventory.hosts[host])
                except KeyError:
                    hosts_left.append(self._inventory.get_host(host))
        return hosts_left
    def update_active_connections(self, results):
        ''' updates the current active persistent connections '''
        for r in results:
            if 'args' in r._task_fields:
                socket_path = r._task_fields['args'].get('_ansible_socket')
                if socket_path:
                    if r._host not in self._active_connections:
                        self._active_connections[r._host] = socket_path
class NextAction(object):