Use python-swiftclient 3.8.1 to run func tests in Python2.7

... because python-swiftclient=3.9.0 causes connection leak in
Pyton2.7, which causes failure in functional tests.
Currently adding constraint in test-requirments.txt is not working
as expected because of global-requirements.txt, so reinstall
pyhton-swiftclient during devstack installation.

Change-Id: If863bc966a1a5d25db40b812daafcf6a95f5dda5

.functests

@@ -16,6 +16,14 @@ shift
 
 ant build_storlets
 
+if [ ${USE_PYTHON3} == "False" ]; then
+    # TODO(takashi): We should use python-swiftclent 3.8.1 to avoid connection
+    #                leak on py2.7(lp#1873435). Remove this once we get a fixed
+    #                version released.
+    pip uninstall python-swiftclient
+    pip install python-swiftclient==3.8.1
+fi
+
 SRC_DIR=$(cd $(dirname $0); pwd)
 cd ${SRC_DIR}/tests/functional
 if [ "$FLAVOR" == "jenkins" ]; then

tox.ini

@@ -48,6 +48,7 @@ setenv =
    STORLET_SAMPLE_PATH={toxinidir}/StorletSamples
    CLUSTER_CONF_DIR={toxinidir}
 commands = {toxinidir}/.functests jenkins
+passenv = USE_PYTHON3
 
 [testenv:venv]
 commands = {posargs}