Support py3.5

This makes the process calls consistently return strings on all python
versions.

Change-Id: Ibda89b467b461b8833515f50a0cf1cc3064cb917

paunch/runner.py

@@ -36,7 +36,9 @@ class DockerRunner(object):
         cmd_stdout, cmd_stderr = subproc.communicate()
         LOG.debug(cmd_stdout)
         LOG.debug(cmd_stderr)
-        return cmd_stdout, cmd_stderr, subproc.returncode
+        return (cmd_stdout.decode('utf-8'),
+                cmd_stderr.decode('utf-8'),
+                subproc.returncode)
 
     def current_config_ids(self):
         # List all config_id labels for managed containers

paunch/tests/test_runner.py

@@ -28,7 +28,8 @@ class TestDockerRunner(base.TestCase):
     def mock_execute(self, popen, stdout, stderr, returncode):
         subproc = mock.Mock()
         subproc.returncode = returncode
-        subproc.communicate.return_value = (stdout, stderr)
+        subproc.communicate.return_value = (stdout.encode('utf-8'),
+                                            stderr.encode('utf-8'))
         popen.return_value = subproc
 
     def assert_execute(self, popen, cmd):

setup.cfg

@@ -16,8 +16,7 @@ classifier =
     Programming Language :: Python :: 2
     Programming Language :: Python :: 2.7
     Programming Language :: Python :: 3
-    Programming Language :: Python :: 3.3
-    Programming Language :: Python :: 3.4
+    Programming Language :: Python :: 3.5
 
 [files]
 packages =