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##### SUMMARY
When trying to install a role, install fails and the role is not found. Investigation shows the role API URL being used to lookup the role information is being truncated in `lib/ansible/galaxy/api.py` line 274, potentially due to the change from `rstrip()` to `strip()` in `_urljoin()`.

##### 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 -->
```paste below
ansible 2.9.0b1
  config file = /etc/ansible/ansible.cfg
  configured module search path = ['/home/calvin/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /home/calvin/projects/ansible/lib/ansible
  executable location = /home/calvin/.local/share/virtualenvs/orion/bin/ansible
  python version = 3.6.9 (default, Jul  3 2019, 17:57:57) [GCC 8.3.1 20190223 (Red Hat 8.3.1-2)]

```

##### 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. -->


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

<!--- Paste example playbooks or commands between quotes below -->
```yaml
```

- Try to install any role from Galaxy

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

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->
The role to be located and installed from Galaxy

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->
The role is not found, even though it clearly exists.

<!--- Paste verbatim command output between quotes -->
```paste below
(orion) [calvin@localhost ansible]$ ansible-galaxy install geerlingguy.nginx
- downloading role 'nginx', owned by geerlingguy
 [WARNING]: - geerlingguy.nginx was NOT installed successfully: - sorry, geerlingguy.nginx was not found on https://galaxy.ansible.com.

```


Additional evidence of where the problem comes from internally:

```
(orion) [calvin@localhost ansible]$ ansible-galaxy -vvv install --server=http://galaxy.ansible.com geerlingguy.docker
[DEPRECATION WARNING]: Setting verbosity before the arg sub command is deprecated, set the verbosity after the sub command. This feature will be 
removed in version 2.13. Deprecation warnings can be disabled by setting deprecation_warnings=False in ansible.cfg.
ansible-galaxy 2.9.0b1
  config file = /etc/ansible/ansible.cfg
  configured module search path = ['/home/calvin/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /home/calvin/projects/ansible/lib/ansible
  executable location = /home/calvin/.local/share/virtualenvs/orion/bin/ansible-galaxy
  python version = 3.6.9 (default, Jul  3 2019, 17:57:57) [GCC 8.3.1 20190223 (Red Hat 8.3.1-2)]
Using /etc/ansible/ansible.cfg as config file
Processing role geerlingguy.docker 
- downloading role 'docker', owned by geerlingguy
> /home/calvin/projects/ansible/lib/ansible/galaxy/api.py(274)lookup_role_by_name()
-> url = _urljoin(self.api_server, self.available_api_versions['v1'], "roles",
(Pdb) l
269                     display.display("- downloading role '%s', owned by %s" % (role_name, user_name))
270             except Exception:
271                 raise AnsibleError("Invalid role name (%s). Specify role as format: username.rolename" % role_name)
272  
273             import pdb; pdb.set_trace()
274  ->         url = _urljoin(self.api_server, self.available_api_versions['v1'], "roles",
275                            "?owner__username=%s&name=%s" % (user_name, role_name))[:-1]
276             data = self._call_galaxy(url)
277             if len(data["results"]) != 0:
278                 return data["results"][0]
279             return None
(Pdb) n
> /home/calvin/projects/ansible/lib/ansible/galaxy/api.py(275)lookup_role_by_name()
-> "?owner__username=%s&name=%s" % (user_name, role_name))[:-1]
(Pdb) n
> /home/calvin/projects/ansible/lib/ansible/galaxy/api.py(276)lookup_role_by_name()
-> data = self._call_galaxy(url)
(Pdb) !url
'https://galaxy.ansible.com/api/v1/roles/?owner__username=geerlingguy&name=docke'
```

Note the truncated URL on the last line of this snippet
"""
        Gets a list of available versions for a collection on a Galaxy server.
        :param namespace: The collection namespace.
        :param name: The collection name.
        :return: A list of versions that are available.
        """
        if 'v3' in self.available_api_versions:
            api_path = self.available_api_versions['v3']
            results_key = 'data'
            pagination_path = ['links', 'next']
        else:
            api_path = self.available_api_versions['v2']
            results_key = 'results'
            pagination_path = ['next']
        n_url = _urljoin(self.api_server, api_path, 'collections', namespace, name, 'versions')
        error_context_msg = 'Error when getting available collection versions for %s.%s from %s (%s)' \
                            % (namespace, name, self.name, self.api_server)
        data = self._call_galaxy(n_url, error_context_msg=error_context_msg)
        versions = []
        while True:
            versions += [v['version'] for v in data[results_key]]
            next_link = data
            for path in pagination_path:
                next_link = next_link.get(path, {})
            if not next_link:
                break
            data = self._call_galaxy(to_native(next_link, errors='surrogate_or_strict'),
                                     error_context_msg=error_context_msg)
        return versions