Use ostestr for test runs

This commit switches to use ostestr for running tests. ostestr
integrates the subunit-trace output that other projects use for test
output. (in addition to some other ui niceties)

Change-Id: Ib5b5225b2a7bfb7897e1efe55181389d1ae095cb

test-requirements.txt

@@ -11,6 +11,7 @@ oslosphinx>=2.5.0  # Apache-2.0
 oslotest>=1.5.1  # Apache-2.0
 requests-mock>=0.6.0  # Apache-2.0
 sphinx>=1.1.2,!=1.2.0,!=1.3b1,<1.3
+os-testr>=0.1.0
 testrepository>=0.0.18
 testtools>=0.9.36,!=1.2.0
 WebOb>=1.2.3

tox.ini

@@ -9,8 +9,8 @@ install_command = pip install -U {opts} {packages}
 setenv = VIRTUAL_ENV={envdir}
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
-commands = python setup.py testr --testr-args='{posargs}'
-whitelist_externals = bash
+commands = ostestr {posargs}
+whitelist_externals = ostestr
 
 [testenv:pep8]
 commands = flake8