##### SUMMARY
Environment variables in plugin do not match Tower credential injector

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
lib/ansible/plugins/inventory/vmware_vm_inventory.py

##### ANSIBLE VERSION
```
ansible 2.8.0
  config file = /etc/ansible/ansible.cfg
  configured module search path = [u'/root/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python2.7/site-packages/ansible
  executable location = /bin/ansible
  python version = 2.7.5 (default, May 20 2019, 12:21:26) [GCC 4.8.5 20150623 (Red Hat 4.8.5-36)]
```
##### CONFIGURATION
```paste below

```

##### OS / ENVIRONMENT
Red Hat Enterprise Linux Server release 7.5

##### STEPS TO REPRODUCE
use vmware inventory plugin with vCenter credential in Ansible Tower
```yaml
---
plugin: vmware_vm_inventory
validate_certs: False
```


##### EXPECTED RESULTS
inventory should be parsed

##### ACTUAL RESULTS
```paste below
 [WARNING]:  * Failed to parse
/var/lib/awx/projects/_16__ansible_inventory/tests/vmware_vm_inventory.yaml
with auto plugin: No setting was provided for required configuration
plugin_type: inventory plugin: vmware_vm_inventory setting: username
```

default: False
            type: boolean
        properties:
            description:
            - Specify the list of VMware schema properties associated with the VM.
            - These properties will be populated in hostvars of the given VM.
            - Each value in the list specifies the path to a specific property in VM object.
            type: list
            default: [ 'name', 'config.cpuHotAddEnabled', 'config.cpuHotRemoveEnabled',
                       'config.instanceUuid', 'config.hardware.numCPU', 'config.template',
                       'config.name', 'guest.hostName', 'guest.ipAddress',
                       'guest.guestId', 'guest.guestState', 'runtime.maxMemoryUsage',
                       'customValue'
                       ]
            version_added: "2.9"
'''
EXAMPLES = '''
# Sample configuration file for VMware Guest dynamic inventory
    plugin: vmware_vm_inventory
    strict: False
    hostname: 10.65.223.31
    username: administrator@vsphere.local
    password: Esxi@123$%
    validate_certs: False
    with_tags: True
# Gather minimum set of properties for VMware guest
    plugin: vmware_vm_inventory
    strict: False
    hostname: 10.65.223.31
    username: administrator@vsphere.local