make testing be non parallel

sphinx and sphinx_testing doesn't appear to be fully concurrent
safe. For now, lets just run in a single process.

Change-Id: I0b1bd24878a7641bc8c456141bf091b48c19619d

tox.ini

@@ -1,16 +1,14 @@
 [tox]
 minversion = 2.0
-envlist = py34,py27,pep8
+envlist = py27,pep8,docs
 skipsdist = True
 
 [testenv]
-usedevelop = True
 install_command =
                   pip install -U {opts} {packages}
-setenv =
-   VIRTUAL_ENV={envdir}
-deps = -r{toxinidir}/test-requirements.txt
-commands = python setup.py test --slowest --testr-args='{posargs}'
+deps = -r{toxinidir}/requirements.txt
+     -r{toxinidir}/test-requirements.txt
+commands = python setup.py test --slowest --no-parallel --testr-args='{posargs}'
 
 [testenv:pep8]
 commands = flake8 {posargs}