##### SUMMARY
If I have a host with a name like `foo` and have variables inside a file `host_vars/foo.yml` inside of a directory properly passed via `--playbook-dir` to the `ansible-inventory` command, vars from that file are not present in the output.

This used to work. The regression was first seen the night of Nov 4, 2019

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
lib/ansible/cli/inventory.py

##### ANSIBLE VERSION
```paste below
ansible --version
ansible 2.10.0.dev0
  config file = /Users/alancoding/Documents/repos/jlaska-ansible-playbooks/ansible.cfg
  configured module search path = ['/Users/alancoding/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /Users/alancoding/Documents/repos/ansible/lib/ansible
  executable location = /Users/alancoding/.virtualenvs/ansible3/bin/ansible
  python version = 3.6.5 (default, Apr 25 2018, 14:23:58) [GCC 4.2.1 Compatible Apple LLVM 9.1.0 (clang-902.0.39.1)]
```

##### CONFIGURATION
```paste below
$ ansible-config dump --only-changed
DEPRECATION_WARNINGS(/Users/alancoding/Documents/repos/jlaska-ansible-playbooks/ansible.cfg) = False
```

##### OS / ENVIRONMENT
Mac OS


##### STEPS TO REPRODUCE
https://github.com/ansible/test-playbooks/tree/master/inventories

host of interest is `group_one_host_01`

Inventory file: 

```
$ cat inventories/inventory.ini 
ungrouped_host_[01:05]
group_one_host_01 group_one_host_01_has_this_var=True
group_two_host_01 group_two_host_01_has_this_var=True
group_three_host_01 group_three_host_01_has_this_var=True

[group_one]
group_one_host_[01:05]
group_one_and_two_host_[01:05]
group_one_two_and_three_host_[01:05]

[group_one:vars]
is_in_group_one=True
complex_var=[{"dir": "/opt/gwaf/logs", "sourcetype": "gwaf", "something_else": [1, 2, 3]}]

[group_two]
group_two_host_[01:05]
group_one_and_two_host_[01:05]
group_two_and_three_host_[01:05]
group_one_two_and_three_host_[01:05]

[group_two:vars]
is_in_group_two=True

[group_three]
group_three_host_[01:05]
group_two_and_three_host_[01:05]
group_one_two_and_three_host_[01:05]

[group_three:vars]
is_in_group_three=True

[all:vars]
ansible_connection=local
inventories_var=True
```

vars file:

```
$ cat inventories//host_vars/group_one_host_01
group_one_host_01_should_have_this_var: True
```

run:

```
ansible-inventory -i inventories/inventory.ini --list --export --playbook-dir=inventories/ | grep -r "group_one_host_01_should_have_this_var"
```


##### EXPECTED RESULTS
`group_one_host_01_should_have_this_var` should be in the hostvars for `group_one_host_01`


##### ACTUAL RESULTS
The string `group_one_host_01_should_have_this_var` is not seen anywhere in the output.

super(InventoryCLI, self).init_parser(
            usage='usage: %prog [options] [host|group]',
            epilog='Show Ansible inventory information, by default it uses the inventory script JSON format')
        opt_help.add_inventory_options(self.parser)
        opt_help.add_vault_options(self.parser)
        opt_help.add_basedir_options(self.parser)
        
        self.parser.add_argument('-l', '--limit', help=argparse.SUPPRESS, action=opt_help.UnrecognizedArgument, nargs='?')
        self.parser.add_argument('--list-hosts', help=argparse.SUPPRESS, action=opt_help.UnrecognizedArgument)
        self.parser.add_argument('args', metavar='host|group', nargs='?')
        
        action_group = self.parser.add_argument_group("Actions", "One of following must be used on invocation, ONLY ONE!")
        action_group.add_argument("--list", action="store_true", default=False, dest='list', help='Output all hosts info, works as inventory script')
        action_group.add_argument("--host", action="store", default=None, dest='host', help='Output specific host info, works as inventory script')
        action_group.add_argument("--graph", action="store_true", default=False, dest='graph',
                                  help='create inventory graph, if supplying pattern it must be a valid group name')
        self.parser.add_argument_group(action_group)
        
        self.parser.add_argument("-y", "--yaml", action="store_true", default=False, dest='yaml',
                                 help='Use YAML format instead of default JSON, ignored for --graph')
        self.parser.add_argument('--toml', action='store_true', default=False, dest='toml',
                                 help='Use TOML format instead of default JSON, ignored for --graph')
        self.parser.add_argument("--vars", action="store_true", default=False, dest='show_vars',
                                 help='Add vars to graph display, ignored unless used with --graph')
        
        self.parser.add_argument("--export", action="store_true", default=C.INVENTORY_EXPORT, dest='export',
                                 help="When doing an --list, represent in a way that is optimized for export,"
                                      "not as an accurate representation of how Ansible has processed it")
        self.parser.add_argument('--output', default=None, dest='output_file',