Prohibit certain versions of requests in test-requirements.txt

This prevents version conflicts when Keystone drags in a too-new
oslo.policy, which blackballs latest requests (but Sphinx would try to
pull it in anyway).

Change-Id: I3b2196fdef9936f1c7d468f9c7c9b9246d3d26fd

test-requirements.txt

@@ -7,6 +7,7 @@ mock
 pylint
 python-openstackclient
 boto
+requests!=2.12.2,!=2.13.0
 requests-mock>=0.7.0 # Apache-2.0
 fixtures<2.0,>=1.3.1 # Apache-2.0/BSD
 keystonemiddleware

tox.ini

@@ -68,8 +68,7 @@ setenv = AUTH=keystone
          CEPH_TESTS=1
          LOG_DEST={envdir}/log
 deps =
-  {[testenv]deps}
-  http://tarballs.openstack.org/keystone/keystone-9.0.0.tar.gz
+  {[testenv:keystone]deps}
 
 [testenv:pylint]
 # Avoid to fail by checking members at lxml dynamically loaded module