Switch to stestr in tox.ini

Change according the Project Testing Interface.

Also cap the version of cmd2 to <0.9.0: newer versions
require python 3.4. It looked like the bug should have been
fixed with 0.9.1 but it is not yet.

See https://github.com/python-cmd2/cmd2/issues/421

Change-Id: Iabb61b2f7991e28b990a9ed26b93af8dfb618b37

.gitignore

@@ -8,3 +8,4 @@ build
 *.swo
 *.pyc
 .testrepository
+.stestr

.stestr.conf

@@ -0,0 +1,2 @@
+[DEFAULT]
+test_path=tests

requirements.txt

@@ -4,8 +4,9 @@
 
 pbr!=2.1.0,>=2.0.0 # Apache-2.0
 
+cmd2<0.9.0
 openstackdocstheme>=1.16.0 # Apache-2.0
 sphinx>=1.6.2 # BSD
-testrepository>=0.0.18 # Apache-2.0/BSD
+stestr>=1.0.0 # Apache-2.0
 testtools>=1.4.0 # MIT
 yasfb>=0.5.1

tox.ini

@@ -8,7 +8,9 @@ usedevelop = True
 setenv = VIRTUAL_ENV={envdir}
 install_command = pip install -U {opts} {packages}
 deps = -r{toxinidir}/requirements.txt
-commands = python setup.py testr --slowest --testr-args='{posargs}'
+commands =
+    stestr run {posargs}
+    stestr slowest
 passenv = http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY
 
 [testenv:venv]