Fix py27 tox

siblings: python2.7 ConfigParser has no __getitem__
Constrain soupsieve to <2 for python2.7
Add python2-dev to bindep for subprocess32

Change-Id: If9d6a0ae1a62a94dcec11f6bf637ffee7f0f4fc9

bindep.txt

@@ -3,3 +3,8 @@ gcc [test]
 # Required for openstacksdk
 python3-devel [test platform:rpm]
 python3-dev [test platform:dpkg platform:apk]
+
+# Required for subprocess32
+python2-devel [test platform:fedora]
+python-devel [test platform:rpm !platform:fedora !platform:centos-8]
+python-dev [test platform:dpkg platform:apk]

roles/tox/library/tox_install_sibling_packages.py

@@ -318,9 +318,8 @@ def main():
 
     changed = False
     for testenv in envlist:
-        testenv_config = tox_config["testenv:{}".format(testenv)]
-        envdir = testenv_config['envdir']
-        envlogdir = testenv_config['envlogdir']
+        envdir = tox_config.get("testenv:{}".format(testenv), 'envdir')
+        envlogdir = tox_config.get("testenv:{}".format(testenv), 'envlogdir')
         try:
             # Write a log file into the .tox dir so that it'll get picked up
             # Name it with testenv as a prefix so that fetch-tox-output

test-constraints.txt

@@ -0,0 +1 @@
+soupsieve < 2.0; python_version < '3.5'

tox.ini

@@ -12,6 +12,9 @@ commands = stestr run {posargs}
            stestr slowest
 
 [testenv:py27]
+deps =
+    -r{toxinidir}/test-requirements.txt
+    -c{toxinidir}/test-constraints.txt
 basepython = python2.7
 
 [testenv:bindep]