The test case should be executed in the test virtualenv for proper cleanup.
Workaround the `stateconf` `TypeError` exceptions under python 2.6

```python
Traceback (most recent call last):
  File "/testing/tests/unit/stateconf_test.py", line 117, in test_state_prefix
    ''', sls='test')
  File "/testing/tests/unit/stateconf_test.py", line 30, in render_sls
    **kws.copy()
  File "/testing/salt/renderers/stateconf.py", line 229, in render
    data = process_sls_data(sls_templ, tmplctx)
  File "/testing/salt/renderers/stateconf.py", line 114, in process_sls_data
    argline=rt_argline.strip(), **kws
  File "/testing/salt/renderers/jinja.py", line 41, in render
    tmp_data.get('data', 'Unknown render error in jinja renderer')
SaltRenderError: Traceback (most recent call last):
  File "/testing/salt/utils/templates.py", line 64, in render_tmpl
    output = render_str(tmplstr, context, tmplpath)
  File "/testing/salt/utils/templates.py", line 102, in render_jinja_tmpl
    loader = JinjaSaltCacheLoader(opts, context['env'])
  File "/testing/salt/utils/jinja.py", line 42, in __init__
    self.searchpath = opts['file_roots'][env]
TypeError: list indices must be integers, not str
```
Merge pull request #6639 from s0undt3ch/develop

Unit test fixes.