Updates for stestr

Per changes to os-testr [1], this patch set updates the code to leverage
stestr and exclude the newly generated .stestr directory

[1] http://lists.openstack.org/pipermail/openstack-dev/2017-September/122135.html

Change-Id: Ic4713af0ad888bd2ca669a5e9de5e9212255e970

.gitignore

@@ -27,6 +27,7 @@ pip-log.txt
 nosetests.xml
 .testrepository
 cover
+.stestr/
 
 # Translations
 *.mo

.stestr.conf

@@ -0,0 +1,3 @@
+[DEFAULT]
+test_path=${OS_TEST_PATH:-./keystonemiddleware/tests/unit}
+top_dir=./

tox.ini

@@ -9,14 +9,15 @@ install_command = {toxinidir}/tools/tox_install.sh {env:UPPER_CONSTRAINTS_FILE:h
 setenv = VIRTUAL_ENV={envdir}
          BRANCH_NAME=master
          CLIENT_NAME=keystonemiddleware
-         OS_STDOUT_NOCAPTURE=False
-         OS_STDERR_NOCAPTURE=False
+         OS_STDOUT_CAPTURE=1
+         OS_STDERR_CAPTURE=1
+         OS_TEST_TIMEOUT=60
          TESTS_DIR=./keystonemiddleware/tests/unit/
 
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
        .[audit_notifications]
-commands = ostestr {posargs}
+commands = stestr run {posargs}
 
 [testenv:pep8]
 commands =