##### 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]
```

group_name = self._inventory.add_group(group_name)
        for name in parent_group_names:
            if name not in self._inventory.groups:
                
                self._inventory.add_group(name)
                changed = True
        group = self._inventory.groups[group_name]
        for parent_group_name in parent_group_names:
            parent_group = self._inventory.groups[parent_group_name]
            new = parent_group.add_child_group(group)
            if new and not changed:
                changed = True
        if real_host not in group.get_hosts():
            changed = group.add_host(real_host)
        if group not in real_host.get_groups():
            changed = real_host.add_group(group)
        if changed:
            self._inventory.reconcile_inventory()
        result_item['changed'] = changed
    def _copy_included_file(self, included_file):
        '''
        A proven safe and performant way to create a copy of an included file
        '''
        ti_copy = included_file._task.copy(exclude_parent=True)
        ti_copy._parent = included_file._task._parent
        temp_vars = ti_copy.vars.copy()
        temp_vars.update(included_file._vars)
        ti_copy.vars = temp_vars
        return ti_copy
    def _load_included_file(self, included_file, iterator, is_handler=False):