api tests to update/delete roles

- added two tests to delete and update role.
As per [PEP 257](http://legacy.python.org/dev/peps/pep-0257/#multi-line-docstrings), the first line of a docstring should be separate. Why? Well, realize that according to the reStructuredText standard, the above is equivalent to this:

```python
"""
@Test: Create a role and delete it @Feature: Role @Assert role deletion should
succeed
"""
```

How about something like this:

```python
"""@Test: Create a role and delete it

@Feature: Role

@Assert role deletion should succeed

"""
```