Remove usage of six

Remove six-library Replace the following items with Python 3 style code.
- six.StringIO

Change-Id: Ia8a28940edc9ca1b26ca0ef5112a44fe5fc6258d

tempest/lib/common/ssh.py

@@ -14,6 +14,7 @@
 #    under the License.
 
 
+import io
 import select
 import socket
 import time
@@ -67,7 +68,7 @@ class Client(object):
         self.password = password
         if isinstance(pkey, six.string_types):
             pkey = paramiko.RSAKey.from_private_key(
-                six.StringIO(str(pkey)))
+                io.StringIO(str(pkey)))
         self.pkey = pkey
         self.look_for_keys = look_for_keys
         self.key_filename = key_filename

tempest/tests/cmd/test_workspace.py

@@ -12,15 +12,12 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+from io import StringIO
 import os
 import shutil
 import subprocess
 import tempfile
 from unittest.mock import patch
-try:
-    from StringIO import StringIO
-except ImportError:
-    from io import StringIO
 
 from tempest.cmd import workspace
 from tempest.lib.common.utils import data_utils

tempest/tests/lib/test_ssh.py

@@ -12,11 +12,11 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from io import StringIO
 import socket
 from unittest import mock
 
 import six
-from six import StringIO
 import testtools
 
 from tempest.lib.common import ssh
@@ -30,7 +30,7 @@ class TestSshClient(base.TestCase):
     SELECT_POLLIN = 1
 
     @mock.patch('paramiko.RSAKey.from_private_key')
-    @mock.patch('six.StringIO')
+    @mock.patch('io.StringIO')
     def test_pkey_calls_paramiko_RSAKey(self, cs_mock, rsa_mock):
         cs_mock.return_value = mock.sentinel.csio
         pkey = 'mykey'

tools/check_logs.py

@@ -17,6 +17,7 @@
 
 import argparse
 import gzip
+import io
 import os
 import re
 import sys
@@ -69,7 +70,7 @@ def process_files(file_specs, url_specs, allow_lists):
         req = urlreq.Request(url)
         req.add_header('Accept-Encoding', 'gzip')
         page = urlreq.urlopen(req)
-        buf = six.StringIO(page.read())
+        buf = io.StringIO(page.read())
         f = gzip.GzipFile(fileobj=buf)
         if scan_content(f.read().splitlines(), regexp, allow_list):
             logs_with_errors.append(name)