<!--- Verify first that your issue is not already reported on GitHub -->
<!--- Also test if the latest release and devel branch are affected too -->
<!--- Complete *all* sections as described, this form is processed automatically -->

##### SUMMARY
<!--- Explain the problem briefly below -->
If a user passes an incorrect username or password via the configuration for a galaxy_server the error message is unhelpful.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
ansible-galaxy
##### ANSIBLE VERSION

<!--- Paste verbatim output from "ansible --version" between quotes -->
```
ansible --version
ansible 2.9.0
  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, Aug  7 2019, 00:51:29) [GCC 4.8.5 20150623 (Red Hat 4.8.5-39)]
```

##### CONFIGURATION
<!--- Paste verbatim output from "ansible-config dump --only-changed" between quotes -->
```
ansible-config dump --only-changed
DEFAULT_JINJA2_NATIVE(/etc/ansible/ansible.cfg) = True
GALAXY_SERVER_LIST(/etc/ansible/ansible.cfg) = [u'automation_hub']


```

##### OS / ENVIRONMENT
<!--- Provide all relevant information below, e.g. target OS versions, network device firmware, etc. -->
RHEL7

##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->

<!--- Paste example playbooks or commands between quotes below -->
```
[galaxy]
server_list = automation_hub
[galaxy_server.automation_hub]
url=https://cloud.redhat.com/api/automation-hub/
username=$INCORRECTUSERNAME
password=$PASSWORD

```

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

##### EXPECTED RESULTS
Actual error from automation hub api is exposed:
```
< HTTP/1.1 401 Unauthorized
< Server: openresty/1.13.6.1
< Content-Type: text/plain
< Content-Length: 40
< x-rh-insights-request-id: 
< X-Content-Type-Options: nosniff
< Date: Thu, 14 Nov 2019 18:05:51 GMT
< Connection: keep-alive
< Set-Cookie: ; path=/; HttpOnly; Secure
< X-Frame-Options: SAMEORIGIN
< 
```
Insights services authentication failed

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


##### ACTUAL RESULTS
generic and not useful error is thrown:

```
ansible-galaxy collection install splunk.enterprise_security -vvv
ansible-galaxy 2.9.0
  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-galaxy
  python version = 2.7.5 (default, Aug  7 2019, 00:51:29) [GCC 4.8.5 20150623 (Red Hat 4.8.5-39)]
Using /etc/ansible/ansible.cfg as config file
Process install dependency map
Processing requirement collection 'splunk.enterprise_security'
ERROR! Error when finding available api versions from automation_hub (https://cloud.redhat.com/api/automation-hub/) (HTTP Code: 401, Message: Unknown error returned by Galaxy server.)
```
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->

<!--- Paste verbatim command output between quotes -->
```paste below

```

headers = headers or {}
        self._add_auth_token(headers, url, required=auth_required)
        try:
            display.vvvv("Calling Galaxy at %s" % url)
            resp = open_url(to_native(url), data=args, validate_certs=self.validate_certs, headers=headers,
                            method=method, timeout=20)
        except HTTPError as e:
            raise GalaxyError(e, error_context_msg)
        except Exception as e:
            raise AnsibleError("Unknown error when attempting to call Galaxy at '%s': %s" % (url, to_native(e)))
        resp_data = to_text(resp.read(), errors='surrogate_or_strict')
        try:
            data = json.loads(resp_data)
        except ValueError:
            raise AnsibleError("Failed to parse Galaxy response from '%s' as JSON:\n%s"
                               % (resp.url, to_native(resp_data)))
        return data
    def _add_auth_token(self, headers, url, token_type=None, required=False):
        
        if 'Authorization' in headers:
            return
        if not self.token and required:
            raise AnsibleError("No access token or username set. A token can be set with --api-key, with "
                               "'ansible-galaxy login', or set in ansible.cfg.")
        if self.token:
            headers.update(self.token.headers())
    @g_connect(['v1'])
    def authenticate(self, github_token):