##### SUMMARY
I'll start by saying that this is a bit of a weird one. It seems that when a handler task is included from another handler and notifies yet another handler, ansible generates spurious warnings and then hangs.

Just to confuse things even more, if you remove the variable reference in `name` OR the `notify` from `bar_handler_tasks.yml`, ansible executes normally.

Another thing to note is that this code (or something very much like it) apparently worked properly in Ansible 2.7.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
handlers

##### ANSIBLE VERSION
```
ansible 2.8.1
  config file = /etc/ansible/ansible.cfg
  configured module search path = [u'/home/agaffney/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python2.7/dist-packages/ansible
  executable location = /usr/bin/ansible
  python version = 2.7.12 (default, Nov 12 2018, 14:36:49) [GCC 5.4.0 20160609]
```

##### CONFIGURATION
N/A

##### OS / ENVIRONMENT
N/A

##### STEPS TO REPRODUCE

`bar.yml`:

```yaml
- hosts: localhost
  gather_facts: no
  handlers:
    - name: play handler 1
      include_tasks: bar_handler_tasks.yml

    - name: play handler 2
      debug:
        msg: play handler 2

  tasks:
    - name: trigger handler 1
      debug:
        msg: trigger handler 1
      changed_when: true
      notify: play handler 1
```

`bar_handler_tasks.yml`:

```yaml
- name: included handler 1 {{ inventory_hostname }}
  debug:
    msg: included handler 1

- name: included handler 2
  debug:
    msg: whatever
  changed_when: true
  notify: play handler 2
```

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->


##### ACTUAL RESULTS
```
PLAY [localhost] **************************************************************************************************************************************************************************************************************************************************************

TASK [trigger handler 1] ******************************************************************************************************************************************************************************************************************************************************
changed: [localhost] => {
    "msg": "trigger handler 1"
}

RUNNING HANDLER [play handler 1] **********************************************************************************************************************************************************************************************************************************************
included: /tmp/ansible_test/kiwiirc/bar_handler_tasks.yml for localhost

RUNNING HANDLER [included handler 1 {{ inventory_hostname }}] *****************************************************************************************************************************************************************************************************************
ok: [localhost] => {
    "msg": "included handler 1"
}

RUNNING HANDLER [included handler 2] ******************************************************************************************************************************************************************************************************************************************
 [WARNING]: 'inventory_hostname' is undefined

RUNNING HANDLER [included handler 2] ******************************************************************************************************************************************************************************************************************************************
 [ERROR]: User interrupted execution
```

prompt_continuous = '> '  
    def __init__(self, task, host, task_vars, play_context, result, next_action):
        
        cmd.Cmd.__init__(self)
        self.prompt = '[%s] %s (debug)> ' % (host, task)
        self.intro = None
        self.scope = {}
        self.scope['task'] = task
        self.scope['task_vars'] = task_vars
        self.scope['host'] = host
        self.scope['play_context'] = play_context
        self.scope['result'] = result
        self.next_action = next_action
    def cmdloop(self):
        try:
            cmd.Cmd.cmdloop(self)
        except KeyboardInterrupt:
            pass
    do_h = cmd.Cmd.do_help
    def do_EOF(self, args):
        """Quit"""
        return self.do_quit(args)
    def do_quit(self, args):
        """Quit"""
        display.display('User interrupted execution')
        self.next_action.result = NextAction.EXIT
        return True
    do_q = do_quit
    def do_continue(self, args):